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Possible overheating of '93 Echelon LX


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I am the definition of a noob.  On a whim, at the beginning of summer I decided it might be fun to buy a boat and see if I like it.  I didn't want to spend an arm and a leg and don't mind losing a little money on the back end if boating is not for me.  Looked all summer and ended up with a 1993 Echelon LX.  I've had to do a lot of research because the boat did not turn out to be as put together as I thought; partly because i didn't know what I didn't know and I got too excited about the boat and didn't look as hard as I should have to begin with.  Apologies up front for the long post, but I think I've done what I know to do, but still have some concerns.

QUESTION/ISSUE:  After doing the maintenance I'll describe below, at idle in the driveway, i'm running about 185-190 degrees at the thermostat housing, exhaust risers are around 200-205, i've got steam out the rear exhaust, and I think it's steam/smoke out of the arrestor on the carb.  I'm fairly mechanical, especially when I don't have to worry too much electrical stuff on the engine.  Am I running too hot, I hear I should be 140-160 and the exhaust risers should be warm, but not hot to the touch.

STORY:  When I looked at the boat, it started (with a spritz of juice in the carb) and idled in the driveway.  He didn't have water hooked up and we ran it for about a minute - know now this is a gigantic no-no for marine engines.  Got on the throttle then back to idle and all was O.K  Bought the boat, took it home, grabbed a friend, and took it to the river (closest boat launch) to see what I had and get my bearings with a new boat.  Launched the boat, it idled, got the truck parked, and back in the boat.  Started it and down the river we went.  about 30-40 minutes down the river at 20 MPH and slowed to talk to some other boaters.  Placed the boat in neutral and it died.  It would start then die, start then die, start then die.  I was able to start it and quickly bump it into gear and got us back to the dock.  With no power, got up river and floated to the dock, then had some nice boaters help get it on the trailer.  I was not a happy camper to say the least; frustrated that I let my emotions get the best of me, etc.   Go home and start my web searches.

Pull the arrestor and realize the carb looks like it could some cleaning.  Get a rebuild kit, pull the carb, clean and rebuild.  More frustration when I pull the carb because it is nasty!!!!!!  Soak it clean it, put it all back together and put it on the boat.  Prime it and in short order the engine fires up.  I play with my fuel mixture and get it to idle well at about 1,000 RPM.  Runs at an idle for 10 minutes or so.  I do have a fake lake hooked up to the boat and I've got water flowing through.  I turn off the boat and start it back up, turn it off, start it up.  I'm happier now because the boat at least starts.  I did throttle up to about 2,500 - 3,000 RPM on the fake lake (I know now even that is no good).  Because there appeared to be more rust around the engine compartment than I initially saw and while looking in the bilge compartment from engine to the transom, I notice there was more debris, gunk than there should be.  Almost as though the boat was stored outside exposed to the elements; could be why it has a nice new interior and carpeting, etc.  Also noticed at this time my vent tubes from the engine compartment to the transom are shot, major holes, etc.  Again, frustration.

Changed the thermostat; used a 160 instead of a 140, cleaned my alarm sensor and temp sensor.  My temp gauge does not work and with the sensor out, it seems to have current when hooked to an ohm meter.  Put it all back together, start the water, start the engine, increase my RPM's - bad move - and after a few minutes my alarm goes off.  That's good that the alarm goes off, but I'm now concerned I'm overheating.  Grab the infrared heat gun and I start checking temps at the thermostat housing, exhaust manifolds & risers, intake manifold, etc.  I slowly start climbing all over.  At about 195 at the thermostat and 220 at the exhaust I shut it down and go back to the internet.  Here's were it really sinks in that I could have really messed things up by running without water, however briefly, and that running high RPM's with water is no good; the culprit is most likely the impeller.  Get a new impeller, replace it, put some dish soap on it to help lubricate, then start the engine.  Starts right up, gets water going through the system and this is where I settle in at about 185 - 188 at the thermostat housing and 200ish at the risers.  For an auto, I'm O.K. with those temps, but I'm reading that this boat is about 20-30 degrees too hot.  Maybe more on the exhaust.  

Being a 93 i read that my exhaust manifold/riser water jackets may be clogged and need to be replaced or cleaned; or that my oil cooler "filter" may be clogged.  Tonight I unhooked the downline hose on the oil cooler, put my finger inside and didnt feel anything but the honeycomb screen.  Pulled the port exhaust riser expecting it be a big mess, but was pleasantly surprised that the passages all seemed clear and the walls between the exhaust and water ports were solid.  

I should mention that after the carb rebuild, the 160 thermostat, and the new impeller, I've got a great sound and idle at about 800 RPM.  It goes in and out of neutral with no problems and throttled up to 1,200 - 1,300 RPM and back to neutral with no problems.  Starts no problems after turning it off.  I plan to go out this Saturday for another break in run, but I'm at a crossroads and don't know what, if anything I should do next.  Am I running hot?  What/why is the smoke/steam coming from the carb?  Why do I have steam out the exhaust when I get to running temp?  Will the temp come down when I'm on the lake with more flow.

Thanks in advance for the help and again, I apologize for the long post.

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Welcome to the crew.  That was a great description of what has happened and what you did about it so far.  I'll offer a few thoughts for you to consider, in no particular order.

Set the idle down to about 650 RPM.  If it won't idle that low, something is wrong.  You didn't mention a complete tune up (plugs, wires, cap, rotor), but that might be a great way to start with a known service schedule. 

Great work on the carb rebuild also.  You didn't post photos of the smoke near the carb, but it could be the PCV system returning crankcase vapors to the intake.  The return hose should point directly at the spark arrestor above the carb.  If the smoke is rising from the manifold below the carb, it may just be some oil that is getting warm.

You are correct that you should have a 160*F thermostat.  The engine should consistently run at 160*F, and the risers may be cooler, but shouldn't be much warmer.  By the way, a good rule of thumb is that you can keep your finger on 125*F indefinitely, but you will think it is very hot.  Anything above about 125*F and you can't keep your finger on it.  The point is that your risers may easily be hotter than that.  An IR temp gun is your friend here, since you can check many areas on the engine and get a feel for what is hot.

Running on a hose may or may not give you enough flow to keep the engine cool.  My hose doesn't seem to have a problem, and I can rev the engine to mid range (in neutral) for extended periods without ever getting over 160*F.  Once you get the engine cooling properly in the water you can experiment with your hose to see if it works for you to run above idle.  You didn't say how you were connecting a hose to your boat.  I use a transom fitting that doesn't leak at all, so I'm sure that I get all the water through the cooling system without sucking air.

If you are sure that you have your impeller installed correctly (a pretty simple job) and no debris in the transmission cooler, I would look for an air leak in the intake side of things, which is everything from the hull fitting to the inlet side of the raw water pump.  Air is much less viscous than water, and any air leak will allow the pump to suck in air before it lifts the water that you want.  Remove every hose from the inlet side, carefully examine, and then reinstall.  Using some sort of goop can help seal any voids, but you probably don't want any permanent adhesion.  A dry fitting has always worked for me, but a stubborn case might need help sealing.  Always use two band clamps on each fitting for water intake and exhaust hoses.

I am working on a group buy discount for stainless exhaust manifolds if you should decide that your iron manifolds and risers are in need of replacement.  The deal got slowed down by a price change at the manufacturer at the last minute, but it seems to be on track again for taking orders within about a month.

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I have a 1996 response, it is similar to your boat but it is fuel injected. My boat never reaches temps above 140 unless there is a problem.  The veins on the raw water impeller broke off once and managed to find their way to the transmission cooler. The first sign of a problem was the MEFI controller going into limp mode limiting the engine to 3000 RPM. Now I change the  impeller every couple of years and have not had issues since. 

It sounds to me like you needed a carb rebuild to solve your idle problem. The rest could just be bad fuel related, fuel filter or pump related. 

My boat has a filter at the rear about 10 inches from the tank outlet and another prior to the fuel pump. If I were you I would spend the 20 bucks and change them out again after your car rebuild and then think seriously about an electrical fuel pump and regulator (6-8lbs).

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1 hour ago, MoonDawg said:

My boat has a filter at the rear about 10 inches from the tank outlet and another prior to the fuel pump. If I were you I would spend the 20 bucks and change them out again...

Not a bad idea.  Another good idea is to completely change the fuel and exhaust hoses.  You don't really want either one to rupture while you are out on the water.

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2 hours ago, justgary said:

Welcome to the crew.  That was a great description of what has happened and what you did about it so far.  I'll offer a few thoughts for you to consider, in no particular order.

Set the idle down to about 650 RPM.  If it won't idle that low, something is wrong.  You didn't mention a complete tune up (plugs, wires, cap, rotor), but that might be a great way to start with a known service schedule. 

Great work on the carb rebuild also.  You didn't post photos of the smoke near the carb, but it could be the PCV system returning crankcase vapors to the intake.  The return hose should point directly at the spark arrestor above the carb.  If the smoke is rising from the manifold below the carb, it may just be some oil that is getting warm.

You are correct that you should have a 160*F thermostat.  The engine should consistently run at 160*F, and the risers may be cooler, but shouldn't be much warmer.  By the way, a good rule of thumb is that you can keep your finger on 125*F indefinitely, but you will think it is very hot.  Anything above about 125*F and you can't keep your finger on it.  The point is that your risers may easily be hotter than that.  An IR temp gun is your friend here, since you can check many areas on the engine and get a feel for what is hot.

Running on a hose may or may not give you enough flow to keep the engine cool.  My hose doesn't seem to have a problem, and I can rev the engine to mid range (in neutral) for extended periods without ever getting over 160*F.  Once you get the engine cooling properly in the water you can experiment with your hose to see if it works for you to run above idle.  You didn't say how you were connecting a hose to your boat.  I use a transom fitting that doesn't leak at all, so I'm sure that I get all the water through the cooling system without sucking air.

If you are sure that you have your impeller installed correctly (a pretty simple job) and no debris in the transmission cooler, I would look for an air leak in the intake side of things, which is everything from the hull fitting to the inlet side of the raw water pump.  Air is much less viscous than water, and any air leak will allow the pump to suck in air before it lifts the water that you want.  Remove every hose from the inlet side, carefully examine, and then reinstall.  Using some sort of goop can help seal any voids, but you probably don't want any permanent adhesion.  A dry fitting has always worked for me, but a stubborn case might need help sealing.  Always use two band clamps on each fitting for water intake and exhaust hoses.

I am working on a group buy discount for stainless exhaust manifolds if you should decide that your iron manifolds and risers are in need of replacement.  The deal got slowed down by a price change at the manufacturer at the last minute, but it seems to be on track again for taking orders within about a month.

Thanks for the information.  I have not replaced the plugs, wires, etc.  That is something on my to do list; since I bought the boat about a month ago and its only been out once, I really want to get some water time before it gets too cold.

The smoke/steam (not really sure, but it's white) is coming from the holes on top of the arrestor.  The Arrestor has the metal cross member, for lack of a better description, that has a tube attached to each end that runs to the valve cover - PCV valve specifically.  Although I rebuilt the carb, I did not clean the arrestor and it may have some varnish on it.  

I have the plunger style fake lake set up.  I've thought about installing some sort of hose hookup; but for the meantime, see my comment about wanting to get on the water instead of working on the boat.  Luckily from the bottom of the hull to the raw water pump is maybe an 18" - 24' run.  There's a brass elbow from the intake on the bottom of the boat, then one hose from there to the inlet side of the raw water pump.  Also, I'm confident the impeller is installed correctly.  The fins are set to rotate and fold over in the same direction as the one I replaced, unless that was installed incorrectly. 

I'm taking the IR with me on Saturday to stay on top of things.  I'll keep you posted.

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2 hours ago, MoonDawg said:

I have a 1996 response, it is similar to your boat but it is fuel injected. My boat never reaches temps above 140 unless there is a problem.  The veins on the raw water impeller broke off once and managed to find their way to the transmission cooler. The first sign of a problem was the MEFI controller going into limp mode limiting the engine to 3000 RPM. Now I change the  impeller every couple of years and have not had issues since. 

It sounds to me like you needed a carb rebuild to solve your idle problem. The rest could just be bad fuel related, fuel filter or pump related. 

My boat has a filter at the rear about 10 inches from the tank outlet and another prior to the fuel pump. If I were you I would spend the 20 bucks and change them out again after your car rebuild and then think seriously about an electrical fuel pump and regulator (6-8lbs).

It could be fuel.  The previous owner said he cleaned the tank and put in a higher octane fuel.  It didn't smell bad.  I have a '55 New Yorker that sat for almost 20 years and the fuel system was shot.  The boat smelled like fresh gas.  I did add a bottle of seafoam to it.  I like the fuel filter idea.  I think I only have one and should probably add a second.  Cheap way to keep impurities out of the system.  I look at the fuel pump, too.

Thanks for the input.

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I would still pull that one water inlet hose and double check that it is not leaking air at either end.  The cover plate for your pump can also suck air, so hopefully you used a new gasket for that as well. 

Cleaning the spark arrestor is easy, and can be done with a spray can of carb cleaner.  Hopefully that will fix the smoke problem.

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Welcome to the crew!

I agree with the other tune up items, and also that your idle should be closer to the 600-650rpm mark.  Also agree on cleaning the flame arrestor, you'll probably be surprised how much stuff comes out of it.  I do it at the end or start of every season, continually spraying thru the metal slats until the spray liquid is dripping/flowing clear thru the whole thing and it usually takes pretty much an entire spray can.

I have steam/vapor coming out of the exhaust and the valve cover vent tubes, normal operation.

There is an audible temperature alarm on your boat, it makes a really loud continuous beeeeeeeeeep noise.  It goes into that alarm for 1)key on ignition but not running, 2)high temperature (don't know what the parameter is), 3)low oil pressure (I think).  It would be good to know if it's working, does your alarm go off if you leave your key on without starting the engine?

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@Sig556 - Congrats on your new boat, the Echelon is the boat that put Malibu in the big 3 category for slalom skiing with Nautique and Master Craft.  A couple of questions, how many hours assuming the hour meter is working and assuming you have the Mercruiser 350 Mag Tournament ski engine.

As for white smoke, that is a sign of water vapor, normal in the exhaust although maybe a minor concern from the valve cover vents that plumb to the carburetor.  I suggest a compression test & leak down test simply to confirm decent compression.  That era engine came with a 140 degree thermostat, reason being salt water use, if temp goes higher that can crystallize the salt in the manifolds.  If you are running fresh water, 160 stat is fine and tends to be current practice.  The exhaust system bleed system on a Merc can fail, it is a rod with springs and balls within the thermostat housing, something you will want to check as the springs tend to corrode and fail.  

Diagnosing engine running issues on a fake a lake tends not to identify problems as you don't load the engine, it takes engine load to make hot running & engine power issues show up.  On the impeller change, always look at the housing for damage & good fit of the impeller.  I tend to check my tstats on the stove before install just to be sure.  An older engine does have the chance for corrosion buildup, particularly the manifolds, the lower part of the cooling passages in the block, the thermostat housing and the head gasket holes can get corrosion.

The transmission cooler is a nice weed / debris catcher, the inlet side tends to hold all the 'crap' leading to a hot running scenario.  Simply pop off the inlet hose and use you finger or forceps to reach in and clean out the junk.  You can add a water strainer between that and the raw water pump, common on many ski boats.

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9 hours ago, Michigan boarder said:

Welcome to the crew!

I agree with the other tune up items, and also that your idle should be closer to the 600-650rpm mark.  Also agree on cleaning the flame arrestor, you'll probably be surprised how much stuff comes out of it.  I do it at the end or start of every season, continually spraying thru the metal slats until the spray liquid is dripping/flowing clear thru the whole thing and it usually takes pretty much an entire spray can.

I have steam/vapor coming out of the exhaust and the valve cover vent tubes, normal operation.

There is an audible temperature alarm on your boat, it makes a really loud continuous beeeeeeeeeep noise.  It goes into that alarm for 1)key on ignition but not running, 2)high temperature (don't know what the parameter is), 3)low oil pressure (I think).  It would be good to know if it's working, does your alarm go off if you leave your key on without starting the engine?

Thanks for the input.  The sensor is working (perhaps not properly, though).  I've disconnected it because it began "notifying" me of overheating at around 155 - 160 after I put the new 160 thermostat in.  I'm putting the port side riser back on tonight, changing the fuel/water separator filter, then heading out tomorrow to see how it works.  I'm also going to install the new temp sensor to see if my temp gauge will start to work; otherwise another trouble shooting issue.

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7 hours ago, Woodski said:

@Sig556 - Congrats on your new boat, the Echelon is the boat that put Malibu in the big 3 category for slalom skiing with Nautique and Master Craft.  A couple of questions, how many hours assuming the hour meter is working and assuming you have the Mercruiser 350 Mag Tournament ski engine.

As for white smoke, that is a sign of water vapor, normal in the exhaust although maybe a minor concern from the valve cover vents that plumb to the carburetor.  I suggest a compression test & leak down test simply to confirm decent compression.  That era engine came with a 140 degree thermostat, reason being salt water use, if temp goes higher that can crystallize the salt in the manifolds.  If you are running fresh water, 160 stat is fine and tends to be current practice.  The exhaust system bleed system on a Merc can fail, it is a rod with springs and balls within the thermostat housing, something you will want to check as the springs tend to corrode and fail.  

Diagnosing engine running issues on a fake a lake tends not to identify problems as you don't load the engine, it takes engine load to make hot running & engine power issues show up.  On the impeller change, always look at the housing for damage & good fit of the impeller.  I tend to check my tstats on the stove before install just to be sure.  An older engine does have the chance for corrosion buildup, particularly the manifolds, the lower part of the cooling passages in the block, the thermostat housing and the head gasket holes can get corrosion.

The transmission cooler is a nice weed / debris catcher, the inlet side tends to hold all the 'crap' leading to a hot running scenario.  Simply pop off the inlet hose and use you finger or forceps to reach in and clean out the junk.  You can add a water strainer between that and the raw water pump, common on many ski boats.

Yes to the 350 mag tourney ski.  I'm at least the third owner.  The guy before me had it about a year.  Prior to that exchange, not sure if original or second owner.  From what I've heard about salt water, etc. and looking in the port side manifold from the riser opening, there is rust, but no crystallization. I suspect its been a fresh water boat.

Regarding the exhaust system bleed component.  When I pulled the T-stat housing there was not one there and I did not replace it either.  Did see it on some diagrams, but wasn't sure if mine wasn't there or did not come with one.  Do I need one?  Could that be part of the problem?

Tonight I'm putting the riser back on, checking my clamps for the inlet side of the raw water pump, checking the water pump is not leaking and secured to specs, change the fuel filter, then top off the tank, and add a couple of cans of sea foam.  Tomorrow out on the lake to see what happens in real world conditions.  I'll keep ya'll posted.

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Update:  I took the boat out yesterday to see if I was O.K. 

First thing in the A.M. I tried to start the boat in the driveway to make sure it would start, because the lake is an hour + drive.  Boat is having trouble starting and I am paranoid at this point and not sure what to do.  I then realize my gas gauge in bouncing in the red zone and must be low on gas.  Head to the gas station, get 5 gallons and add that to the tank.  Starts up and idles, sounds good, and my temps are O.K.; that is they are similar to that stated previously.  Also mention that when I put the port side riser back on after using a brass brush to clean the ports, etc. in the boat I was getting temps around 140-150 off that riser while the starboard riser was still coming in at 190-200.  Should have not gone to the lake and pull the manifolds and other riser.  However, had I done that, I would not have this awesome experience.  Isn't that what life is about. - the stories (4x4 stuck on an incline in the mud on a service rad with the only option is driving to the bottom, calling a friend to bring shovels to knock down an embankment to drive the truck onto the road below (was also Mother's Day).  Or looking at your girlfriend in the passenger seat, then looking back at the road only to find the road isn't there and ended driving off the road down a 50-75 embankment flipping the car multiple times landing on the roof (10 PM on winding backroad on Memorial Day).  There are many more, it's my life and a grand one it is.

Get to the lake, boats in the water at the dock, starts fairly easily and idle it waiting for my friend to come back from parking the truck.  Move away from the dock, and slowly make our way out of the no wake zone - say 125 - 150 yards.  no major issues at this time.  Then it gets bad.  

As a new boater, didn't think to turn the bilge pump on b/c previous outing did not have any issues - this comes into play in a few minutes.  Because I did well coming out of the marina, I'm get excited and overconfident.  Head out across the lake and run it up to about 2,500 - 3,000 RPM.  Sounds good, moves well; slow down quickly and place into neutral (original issue it would die and not start) and no problems.  curious about well the boat would get moving from a stop, drop the hammer.  Like the feel.  Now in the middle of the lake doing about 22 MPH and my pass sitting in back says I've got water coming in through the bilge bay.  O.K.  That's idiot move number one; turn the bilge pump on and see what that'll do.  The plugs were in because I put both in.  Only think I can think is one or both of the plugs did not get tighten enough because I never had this problem in the driveway - but that could have been a not surrounded by water issue.  around the same time I occasionally smell what I believe is rubber burning/melting.

A buddy of mine calls it butt vision (hindsight), I should have stopped the boat and tried to deal with the water issue, but my instinct was to turn back to the marina and try to get closer to the shore.  I did mention that I was in the middle of the lake - probably another mistake, I should have stayed closer to the shore while testing.  Being concerned about taking on water, I'm not thinking about much else; when my other passenger tells me I've got white smoke coming from the exhaust.  Completely forgot about my overheating issue b/c I was worried about sinking.  At this point, the water in the boat is going down and I'm less worried about that.  As the smoke gets a little thicker I decide its best to turn it off, let the water pump out of the boat and try get some help back to the marina.  I did get towing insurance, but I was clueless on how to actually make that happen.  

I'm sitting in the middle of the lake, pumping water out of my boat, now I smell the burnt rubber again, and I have 50 different things going through my mind - boat sinking, boat catching fire, how to get a tow, can I just wait the whole thing out and limp back to the marina, and I am i still overheating, and on and on.  Thankfully another boater noticed what was happening and gave us a tow back to the marina.  got the boat on the trailer and up to the parking lot.  Now comes the wild Idea to check temps.  My risers where in the 195-200 range, so I really have no idea how hot the got on the lake.  - see my previous comment about forgetting that part.

Short story, I had almost decided to take it straight to a mechanic because I'm at my wits end.  Then after some time, I decided I'll give it one more go and pull all of the hoses, pull the risers and manifolds, do what I can to flush the exhaust from the riser to the back of the boat; don't know if this could be the problem if its clogged there.  Since I'm doing it, might as well pull and clear all the hoses.  If that doesn't work, then its to the mechanic. 

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Wow, not a good time.  But hey you didn't flip it over, so in some ways you're ahead right?

Did you determine where the water was coming from?  It sounds to me like a hose broke free and you were no longer pumping water thru the engine & exhaust and instead it was pumping into the boat.  

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6 hours ago, Michigan boarder said:

Wow, not a good time.  But hey you didn't flip it over, so in some ways you're ahead right?

Did you determine where the water was coming from?  It sounds to me like a hose broke free and you were no longer pumping water thru the engine & exhaust and instead it was pumping into the boat.  

Honestly, once I got back to the dock and the boat loaded; I was done for the day.  I suspect one of two things for the water, 1) is that a hose burst/cracked and let water in, or 2) the bilge plug was not tightened enough - but the more I think about that, I'm not sure if enough water could get in the boat that way.  I probably won't look at any of that until Saturday when I pull all the houses, check for obstructions, and clean the manifolds and risers; hopefully I can ID it then.

Thanks for the help all.

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Not sure I got the sequencing correct from your post, but with the following items mentioned - water accumulating in the bilge & white smoke from the exhaust and burnt rubber smells here is a potential scenario:   The raw water pump outlet hose between the raw water pump and the transmission cooler or prior to the circulation pump (what is the water pump on a car or the engine itself) either failed or popped off.  This creates a situation where the raw water pump is pumping lake water in to the bilge and not feeding the engine itself which is running leading to hot exhaust burning the rubber exhaust hoses and when it hits the cool water still in the mufflers along the floor it creates white smoke.  Do you recall if you hear an exhaust note change (louder) that is a clue as to what is happening.  When you shut off the engine, the raw water pump stops and no longer pumps water in to the bilge.

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@Sig556 - Congrats on your purchase, great to have another Malibu owner on the site and welcome to the crew.  I sense some enthusiasm pulling you ahead of some safety steps in the process of getting your boat out on the water.  Things on the water can go bad quickly and have unfortunate and or costly results.  From your description, I would take a step back and do a comprehensive front to back check on the boat, you can find good check lists online.  I also suggest a boater safety course, your local sheriff or marine department will do it for free or they will have regional classes.  Good for everybody that intends to be on the boat and particularly anybody who will captain the vessel.  Ski boats don't handle like a typical I/O or outboard, there are particular nuances that need to be learned (backing up in reverse, not running over the ski rope, leaning to not swamp it, etc).  Your local ski boat dealer (any brand) should have a staff member that is competent and any ski boat owner will probably be more than happy to show you the ropes.  A local ski club would also be a great resource of enthusiastic tournament boat owners willing to help.

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Rack:  Thanks for the pics and your experience.  I'm not doing too much on the boat this week as I've got work stacked up and some tax filing deadlines Oct 15 plus a bunch of audit work that i need to get done.  I think I mentioned it earlier, but before I throw my hands up and take it to a mechanic I'm going to remove the riser to muffler tubes, pull the riser and manifolds to check them out and clean them.  That gives me better access to the plugs, which will be removed, inspected and most likely replaced.  Then I'm going to start at the hull and  remove the hull to raw water pump hose, inspect & replace as needed, probably need to replace the impeller again and maybe the housing, then on to the rest of the hoses as I work my way around the engine and the water passages.  I'll flush the oil/transmission cooler, pull the t-stat housing again and clean it up - verify the t-state is working, too. Not sure if it may be an issue, but I'll probably check the exhaust tubes from muffler to transom in the off chance there is a blockage that is not allowing proper air flow.  Once I've confirmed no blockages, good hoses, tight fitment and properly secured, if it doesn't cool down, then I'll take it in.

Not sure I mentioned, but I did remove the port riser, brushed it out with a brass .30 cal rod (fit great in some passages) then soaked some of it in Evaporust.  Rinsed it all off, reinstalled, started up the engine and at temp, the port riser was running 145 compared to the starboard at 195.

Woodski:  Thanks for the tips.  I have done some online boat safety stuff, but you are probably correct that wanting to get out on the water made me rush a few things.  Had the boat out twice and I do realize my skills are limited; each trip was supposed to be a get the boat on the water and let me get a feel for driving a boat, etc. before I even think about my ski/tow capabilities.  I don't recall changes in the engine - note or tone.  And I have not spent any time in the engine compartment to see if a hose came loose, cracked, split, or some other component failed.  

I'll look into the boater safety course.  I took the motorcycle safety course when I learned to ride 20 years ago, should probably do that for the boat.

I'll keep you posted.

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Afterthought.  Where is a good place to get new hoses for the boat?  Most of them seem pre-formed and it makes sense to do that since they wrap around the correct engine components.  I've got a 350 Magnum Tournament Ski with a 4bbl weber.  Should I need to replace any exhaust or fuel lines, any suggestions, there?

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8 minutes ago, Sig556 said:

Afterthought.  Where is a good place to get new hoses for the boat?  Most of them seem pre-formed and it makes sense to do that since they wrap around the correct engine components.  I've got a 350 Magnum Tournament Ski with a 4bbl weber.  Should I need to replace any exhaust or fuel lines, any suggestions, there?

I would recommend changing the fuel, exhaust, raw water intake, and engine hoses in addition to the belt(s). 

Honestly, I would shop around for prices on hoses that are sold by the foot.  Make sure you get marine A1 fuel hose (probably 5/8") and hard wall marine wet exhaust hose in the correct size (probably either 3.5" or 4").  Basically, look at what is on your boat and replace it with the same rating.

Skidim.com or maybe Bake's (join this site for a discount) may have some of them.

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If you do not know the age of your fuel lines, replace them by all means.  Hoses of that era are not ethanol fuel compatible so updating is a must do.  Given the hot exhaust episode, replacing them is also a safety precaution.  I would remove them and look at the insides, good chance they are blistered, and if age is a question replace them as a safety precaution, a split in the ones near the transom will transition your boat to a hot tub as they are below the water line.  With old fuel lines, a carb rebuilt and/or cleaning is a good preventative maintenance step.  Read up about ethanol fuels and boating, many factual articles available.  Boating magazine is a good source for marine articles, products and information.

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On 10/6/2021 at 9:28 PM, Sig556 said:

Afterthought.  Where is a good place to get new hoses for the boat?  Most of them seem pre-formed and it makes sense to do that since they wrap around the correct engine components.  I've got a 350 Magnum Tournament Ski with a 4bbl weber.  Should I need to replace any exhaust or fuel lines, any suggestions, there?

I found a good guy on eBay when I was replacing my hoses. Jim's Marine out of FL. Mom and pop place with great prices and service. You can email him at [email protected]. He will send you the catalog or you can call him at 813-885-4631.

Edited by BlindSquirrel
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a habit I try to employ when I have not used my boat in a awhile, 1st outing of the year or anytime I smell something or the temp gauge seems off is to move all the stuff out of the way, especially towels and ski line and open the engine cove and look for water or fuel squirting around or anything amiss while the engine is running.   I def have been in a boat where the intake water hose was not attached properly and the boat was only getting partial water supply, the rest dumping in the bilge.

do not run a boat with out a working temp gauge and a temp alarm. it can get very expensive very fast

it sounds like you solved almost all of your problem rodding out your riser..  finish the other side.

"port riser, brushed it out with a brass .30 cal rod (fit great in some passages) then soaked some of it in Evaporust.  Rinsed it all off, reinstalled, started up the engine and at temp, the port riser was running 145 compared to the starboard at 195".

I think 195 on the riser is way too hot and should be closer to the 145 temp.

the rubber exhaust tubes can collapse internally from age and from overheating.  that will block the flow of outgoing water and cause further overheating.

if you were getting 195 off the one riser in the driveway, I cant imagine how hot the was at (high) cruising speed.

If your boat is running hot the last thing you want to do is run it at high speed.

I would always use a 140 temp thermostat on a carb boat. 160 on fuel injected.

I don't know how the water diverter on the thermostat housing works on a mercruiser block. it might be worth investigating.

a lot of times the problems are simple, often related to the last thing you touched.

you've gotten a bunch of advice on a bunch of parts to replace.  I really try to only replace one thing at a time then run the boat.

different engine but indamar says exhaust riser temps can vary  and from 100 to 160 is ok.

my rule if thumb if you have to pull your hand away its too hot.

I had good luck with these guys buying hose . though on my boat its 3" yours is probably different.

exhaust hose suppliers tridentmarine.com
https://tridentmarine.com/product/trident-flex-marine-wet-exhaust-water-250100/#.XvFL-_J7mpu
Vetus Exhaust

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