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Water discharge temps 93 Merc 5.7


BigCountrys93EuroF3

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BigCountrys93EuroF3

Hi, New to the forum. Hello to all.  First time Malibu and inboard owner. Very familiar with engines, I/o's and fix most of my own boats, cars, Motorcycles etc.  

Before purchase a compression test was performed and passed. Boat is running great.  

I was running the boat in the driveway with the toilet plunger hooked up for water underneath and once the boat was fully warmed up I noticed a big difference in water discharge temp from the starboard exhaust (much warmer) vs port exhaust.  By feel it seemed close to 15 degrees or more difference.  I touched both of the valve covers on the engine and it didn't feel like the motor was too hot on either side.  

Is this normal? Thanks in advance, Jeff

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 Jeff,  Glad you brought this up. I have a 1992 Euro f3 Sunsetter with the Mercury 350 Magnum. I'm The original owner from 1992.

  I had an over heat alarm on an outing a few years ago. The exhaust Manifolds were so hot you could not touch them. 

I checked for debris in the trans cooler and all the hoses, the pick up hose ect. Nothing found.

I ended up replacing the T stat and the pivot valve and all the hoses , I thought that the manifolds were not getting enough water flow.

Took it out to the lake and checked the temp of the manifolds. the port side was hotter than the starboard side by about 40 degrees.( But it was a hot sunny day) But the engine temp gauge was normal.

In the driveway I ran it with a garden hose and the exhaust water was hotter on port side but not not by much.

Just because the engine temp is normal does not mean the manifolds are getting cooled if they get too hot they will melt the inside of the flexable exhaust hose.

I had planned to take this in and have the exhaust elbows pulled and inspected but  got too busy so the boat hasn't been out for a while. My Local Malibu dealer won't work on my boat because its too old. 

I understand that the exhaust elbows should be removed, inspected and a New Gasket in stalled to prevent water from getting into the Exhaust ports. This is on my list to be done before I take it out again.

Years ago I owned  a Off shore Boat ( Salt Water) and had to totally replace the exhaust Manifold every 3 years because they would get block from the salt. My Malibu has never been in salt water.

With this concern I asked my "then" dealer if the manifolds ever have a problem with blockage. He had never heard of this issue, That said, Your boat is the same age as mine so age might be the issue rather than Hours.

If you find the issue PM me and let me Know what you found and I will do the same.

On 6/14/2021 at 1:29 PM, BigCountrys93EuroF3 said:

Hi, New to the forum. Hello to all.  First time Malibu and inboard owner. Very familiar with engines, I/o's and fix most of my own boats, cars, Motorcycles etc.  

Before purchase a compression test was performed and passed. Boat is running great.  

I was running the boat in the driveway with the toilet plunger hooked up for water underneath and once the boat was fully warmed up I noticed a big difference in water discharge temp from the starboard exhaust (much warmer) vs port exhaust.  By feel it seemed close to 15 degrees or more difference.  I touched both of the valve covers on the engine and it didn't feel like the motor was too hot on either side.  

Is this normal? Thanks in advance, Jeff

 

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If the boat was tilted in the driveway the lower side could / would be cooler to the touch.  You can verify by watching output volumes at the exhaust tips.  Probably okay but could also be some blockage restricting flow.  A good way to confirm is either on a flat surface or simply checking when boat in the water.  Suggest you buy a cheap thermal temperature gun from H-D, Menards, Lowes, Harbor Freight etc. as a handy tool.  Good for checking temps all over the engine.

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On 6/14/2021 at 1:29 PM, BigCountrys93EuroF3 said:

Hi, New to the forum. Hello to all.  First time Malibu and inboard owner. Very familiar with engines, I/o's and fix most of my own boats, cars, Motorcycles etc.  

Before purchase a compression test was performed and passed. Boat is running great.  

I was running the boat in the driveway with the toilet plunger hooked up for water underneath and once the boat was fully warmed up I noticed a big difference in water discharge temp from the starboard exhaust (much warmer) vs port exhaust.  By feel it seemed close to 15 degrees or more difference.  I touched both of the valve covers on the engine and it didn't feel like the motor was too hot on either side.  

Is this normal? Thanks in advance, Jeff

1907555716_TstatManifold.jpg.8d1887e2f270a088114a9fedaf5b4828.jpg193736542_ExhaustManifold.jpg.66b0e70b88e2781fca5476abd9a9f177.jpg1383982682_350magnumcoolingsystem1992.jpg.8febc992f656cd5930e6e7f7ee36671c.jpg

Edited by Rack
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Above is the cooling system for a 1992 Mercruiser  

Some diagrams don't show the "T" stat manifold  that has the Pivot Valves with the Hoses going to the exhaust Manifold Elbows. Mine does.

I have replaced the pivot valves and cleaned the ports of rust. This helped lower the temp at the elbow, but I'm still going to pull the elbows to look for restrictions.

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BigCountrys93EuroF3

Hi and thank for all the input and info.  So I found my thermostat was leaking slightly and when I replaced the gasket I did not have the correct plastic ring insert to go with it as my orginal was half gone.  So, got the right ring, replaced thermostat and gaskets etc. Leak went away started up the boat lil smoke came from the impeller housing and then a noise and of course too hot so turned it off. Pulled the impeller and it was down to the shaft with rubber on it but all fins were broke off. Side note, this boat had someone who hackjobbed things. First one being only one nut was hold the impeller housing/ pulley to the motor bracket, second one being, when I removed the t stat top metal cap, someone had another wet dream to hack it and rather than cleaning up the surface for a new gasket, they decided to just add another make shift gasket to it. I never understand short cuts, laziness, and or not doing things correctly. 

On friday my buddy sent me home with his infrared gun (great tool, I am buying one this week, given I work on all my own stuff I don't know why I didn't have one already).

So after all the t stat and impeller non sense I started it up and the exhaust water temps were equal, water volume coming out the exhaust was equal and all parts of the motor I shot were in acceptable temps.  My temp gauge is inconsistent, my guess is the sending unit is bad and I have a new one to put in. 

One more side note, took her out on the water brought my tools and infrared gun to check motor periodically while out. All went well.  Love the sound of that 5.7 screaming under load at 4k rpm.  Always wanted a used ski boat and I couldn't be happier with it. I will just keep fixin her and give her what she needs and I will most likely keep this boat for 10 years or longer.

All the replies were great insight and very helpful, and I have made mental notes of it all.  

Thx, Jeff

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BlindSquirrel
6 minutes ago, BigCountrys93EuroF3 said:

 I never understand short cuts, laziness, and or not doing things correctly. 

 

Hey at least you got a thermostat in there... When I bought my boat, mine was MIA. I try to give the benefit of the doubt on people just throwing things together so they "work". Maybe mine was over heating on the lake and they had to do it get home. Then realized it will run "fine" without it and never got around to really fixing it. Yours.... maybe the housing was so out of level, it needed two gaskets not to leak? Since boating time is limited I assume that is why there is a good opportunity to do stuff like that. Certainly not making excuses for pure laziness, as there is plenty of it out there...and very annoying when you have to clean it up. 

When you say the gauge is giving inconsistent temp readings, do you mean it constantly moves? Mine moves around often with the opening and closing of the thermostat. It stays pretty close to the 165 mark. +/- 10 degrees or so depending if underway or not. But does move a good bit.

 

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BigCountrys93EuroF3
Posted (edited)

Hehe, yea I here ya. Def some random reasons why people do goofy stuff like your thermostat missing.  

So my temp gauge is moving around as you stated yours does. But then at times its reading 200 ish  plus or minus and the high temp indicator light on the dash is constantly on. My infrared gun with multiple areas checked doesn't reflect any of the temp gauge high readings.  Any thoughts?

Edited by BigCountrys93EuroF3
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BlindSquirrel
1 hour ago, BigCountrys93EuroF3 said:

Hehe, yea I here ya. Def some random reasons why people do goofy stuff like your thermostat missing.  

So my temp gauge is moving around as you stated yours does. But then at times its reading 200 ish  plus or minus and the high temp indicator light on the dash is constantly on. My infrared gun with multiple areas checked doesn't reflect any of the temp gauge high readings.  Any thoughts?

Yeah, I would agree with you then on it possibly being a sensor since you independently verified it's not overheating. However, I don't know where the temp sensor is, but I bet @formulaben does. 

This is all assuming you cleaned out the transmission cooler filter of the pieces of your old impeller. (assuming your engine has one)

Edited by BlindSquirrel
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BigCountrys93EuroF3

Ok thx gentleman.  Helps to see the pics. Mine is set up differently of course, I do recognize the trans cooler as I saw a video on it.  And I did in fact find my temp sensor as well as it needed to be disconnected to install the two thermostat gaskets. 

A friend of mine mentioned to run a fresh set of wires first to determine there is not a short.  I will do some troubleshooting this week on it.  Speedo and fuel gauge aren't working either.  I am gonna start by looking behind the dash to see the wiring on the gauges and go from there

 

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On 6/21/2021 at 12:51 PM, BlindSquirrel said:

Yeah, I would agree with you then on it possibly being a sensor since you independently verified it's not overheating. However, I don't know where the temp sensor is, but I bet @formulaben does. 

This is all assuming you cleaned out the transmission cooler filter of the pieces of your old impeller. (assuming your engine has one)

Jeff,    BlindSquirrel is correct. 

Pull the hose on the Trans cooler. Its on the portside near the front motor mount. Take the back hose off and use your smart phone to take a picture. You won't be able to get your head in there to see.

 Or just Use a mirror.   If you find rebris in the cooler, You should pull the other end of the hose at the pump and flush with a garden hose while you have the hose disconnected at the cooler.

If you find parts of the impeller in the cooler than pull the front hose on the cooler and flush backwards. 

Let use know how it turns out.  

IMG_3317.JPG

IMG_3319.JPG

Edited by Rack
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BigCountrys93EuroF3

Ok, thx.  I will check it out this week and post an update

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BigCountrys93EuroF3

Also, what app are you guys using to post pics into threads? I used to use photo bucket, but now they want money from me to use the app.  

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BlindSquirrel
2 hours ago, BigCountrys93EuroF3 said:

Also, what app are you guys using to post pics into threads? I used to use photo bucket, but now they want money from me to use the app.  

I use Flickr. It's free and easy to use.

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BigCountrys93EuroF3

Good call gentleman on the trans cooler check. Just one larger chunk of impeller in there but obviously could have been more. I back flushed it as well.  I have picks of the toasted impeller as well. I put in a whole new impeller housing. And here's also a few pics of the old girl

 https://www.flickr.com/photos/[email protected]/shares/q7L09j

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BlindSquirrel
1 hour ago, BigCountrys93EuroF3 said:

Good call gentleman on the trans cooler check. Just one larger chunk of impeller in there but obviously could have been more. I back flushed it as well.  I have picks of the toasted impeller as well. I put in a whole new impeller housing. And here's also a few pics of the old girl

 https://www.flickr.com/photos/[email protected]/shares/q7L09j

You're close on posting images. Just make sure you, within Flickr, click on the one photo you want to show up. Then copy and paste that address, and it will add it to your post. :thumbup:

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BigCountrys93EuroF3
2 minutes ago, BlindSquirrel said:

Malibu Boat Pics

 

So it looks like I see some trans fluid leaking inside? 

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2 minutes ago, BigCountrys93EuroF3 said:

So it looks like I see some trans fluid leaking inside? 

Is it really red, oily fluid?  If you are going by the color, you may be seeing the red patina on the copper tubing inside the exchanger.

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BigCountrys93EuroF3
4 minutes ago, justgary said:

Is it really red, oily fluid?  If you are going by the color, you may be seeing the red patina on the copper tubing inside the exchanger.

Posted just now

Good call. I would have to pull the hose again to stick a cotton swab inside to know for sure. I am just going off my pic that I see above. 

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Even if it comes up just water, probably worth checking trans fluid is not milky.  That era Merc setup did recommend hydraulic fluid for the trans.  ATF is also approved although my experience is hydraulic fluid results in a smoother, quieter operation.

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Glad to see you got it worked out. This forum is a great source of information. When you get the cooling system working we will have to work on the swim step LOL 

Its a boat it never ends

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