Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Bad day on the lake

Recommended Posts

This Saturday started out as a great day on the lake mid 90s sunny skies and calm water. With the lake being smooth as glass we started out slalom skiing. I took a good run then my neighbor got behind the boat. We were cruising along at about 34  mph (5000rpm) when all of a sudden the bilge alarm comes on and their is smoke pouring out of the blower vents at the back of the boat. I immediately put the boat in neutral and shut it off. I opened up the engine area to find the outlet side of the raw water pump had come off. When i looked back at the gauges the boat temperature was reading 230 Deg F. We waited approximately 15 to 20 minutes for the engine to cool down and re-attached the water hose to the engine. Once reattached the engine started right up and the temperature came back down to 160. We idled back to the dock to do a check of the boat.A Car mechanic buddy took a look at everything it all seemed fine so we went back out for a few hours with no problems.

Boat- 2014 VTX with monsoon 5.7 104 hrs and fresh air exhaust.

Follow up.- After reading all the stories online looks like i may have been to quick to judge the all OK. These are the things I think i should do as follow up but looking for some advice from others.

1. Check and potentially replace exhaust hoses and muffler.

2. Replace raw water impeller.

3. Oil change.

4.Compression check.


1. Do i need to be worried that I damaged the exhaust risers or Cat converters?

2. Does water stay in the engine block if you loose input water?

3. Trying to figure out what might have caused this. We have been our many times skiing, surfing and other this season with no problems. I would have thought if the hose was loose it would have given out first time out? could picking up sea weed or other have done this?

4. Any other precautions i should take? Ultimately safety is my biggest concern want to have a safe boat for the family to go on.


Sorry for the long post any help would be great.


Edited by dinovtx
Link to comment

The impeller should be fine if it was the outlet, since it sounds like it was still pumping a lot of water.

In most cases, no water will not stay in the engine. There is a circulation pump on the engine that circulates water inside of the engine. More than likely, that would end up pushing most of the water out of the engine.

It's just dumb bad luck. That little raw water pump can push some serious water, so it probably just built up too much pressure. You can double up on clamps if you're worried about it happening again.

Link to comment

1. Do i need to be worried that I damaged the exhaust risers or Cat converters?   The exhaust risers will be fine, the cat converters IDK, but why worry about it now.

2. Does water stay in the engine block if you loose input water?   No, if the thermostat is open, the circulation pump should empty the engine, although since there is no more water being pushed into the circulation pump, it probably won't pull the water out.  IIRC, the circulation pump does not prime and suck, it just spins and pushes.

3. Trying to figure out what might have caused this. We have been our many times skiing, surfing and other this season with no problems. I would have thought if the hose was loose it would have given out first time out? could picking up sea weed or other have done this?   Did the hose get removed during winterization?  Most likely someone did not tighten the clamp when they put the hose back on.

4. Any other precautions i should take? Ultimately safety is my biggest concern want to have a safe boat for the family to go on.    If the engine runs fine, then just run it.  Check the oil occasionally for milky condition which would indicate water in the oil.   Once or twice a month check for leaks around the hoses.

The 230 engine temp you reported is not likely an accurate indication of your engine temperature.  If you read it after you shut down, it will be higher since it is only a water temp gauge. No water in the block or water not circulating will cause it to read differently than when water is being pumped thru. The smoke you saw was most likely just steam from lake water being spilled on or near a hot engine.

Since it is late June, just take it back out and see how it goes.  Like old jeep mentioned, it should be fine.  


Link to comment

i'd take a moment to look for blockage at the trans cooler.

if you picked up some trash or too much seaweed it could plug the cooler and that could lead to big pressure on the output side of the pump which, in turn, could cause that hose to go.

  • Like 2
Link to comment

With the rate of that pump at 5000 RPM, the bilge will fill up right quick.  You likely didn't do any damage in the short amount of time it'd take to fire the bilge pump.  As @Bozboat said, your temp reading of 230 isn't necessarily indicative of an issue as you were measuring the temperature of stationary water that had time to heat up on the hot block.  The temperature of flowing water is what you want to see around 160.  Hook it all back up and go for a ride.  Check temps underway and do the hand check on the manifolds to ensure they both feel good and warm.  If you have a fake-a-lake, or a skier in tow, you should see water dumping out both exhaust ports.

Link to comment

One precaution would be to double hose clamp the pressure side hoses.  When you check your rubber hoses, also check any of the plastic exhaust manifold fittings.

Is it accurate to assume the hose clamp was not broken but just loose and allowed the hose to pop off, sounds that way from your post?  The raw water pump is rated at pretty close to 8-10gpm for every 1000RPM so that can give you an idea of how much and how long it was disconnected.

Link to comment

Hey everyone thanks for your posts. To answer a few questions above.

Yes the hose clamp was on and on fairly tight and not broken. I checked them at the start of the season in late April. We had put 10hrs on the boat since the start of the season with no problems.

I was worried that the temp reading might not be correct if the water had left the block. So it sounds like it actually might have been hotter than the 230 reading. 

Good call out on getting a new clamp. It does look fine but never know. 

Yes the clamp was removed during winterization but was checked at the beginning of the season. 

Thanks for the excellent call out on checking the trans cooler for something that may have gotten stuck. 

Link to comment

Similar thing happened to me Saturday night, as we were coming in.  In my case, the cap for what is presumably the heater circuit came off.  Auto bilge warning came on, my wife who was driving asked me why, I looked, and the bilge was full, and water was splashing all over teh place.  Temperature was 120, which should have alerted me that it was the system, but I was afraid we were taking in water from a leak, so I told her to just get us home.  After everythign was drained, I put the boat back in the water to look for a leak, but found none.  Started it, and found it coming out of there.  Found the cap, and replaced it.


In my case, that cap had never been removed.  The clamp was tight, but apparently not tight enough.  It is a bit disconcerting.  WIll check all my clamps before I go back out.  Pretty sure that the water in my case was where it would normally recirculate if the t-stat is closed, and that I"m okay.  But overall system pressure would certainly be lower, so I am a bit concerned that maybe I wasn't getting enough water into my manifolds, though it didn't smell or anything.  


My primary concern, and what I'd be worried about in your case, too, is the head gasket.  There wasn't any sign of oil when the water was in my bilge, but there was so much that it would be easily overlooked.  WHen I start it for the first time, I'll just see how easily it starts, and if it is rough.  Will also check the dipstick to see if there are any signs of water in the oil.  If all of that checks out okay, then I will probably be fine.  Do beware that if you open the oil fill cap on the valve cover that it may have a milky look to it.  This is pretty normal, you get enough condensation in the crankcase vapors from blowby that it will tend to somewhat condense on the cold spot, which is that cap.  Don't know if these engines do that, but some do.  Main place to check is the dipstick.  Although, like I had said, if it has a bad head gasekt, it'll probably be hard to start and run rough.

Link to comment

Loose hose clamps is one of the reasons auto manufactures use spring type hose clamps. They continue to squeeze the hose even after the hose has settled due to thermal cycles, age etc.  The "one size fits many" screw type, while they appear to be a more robust design, aren't as maintenance free.

Edited by MadMan
  • Like 2
Link to comment

I run my race car at 240 on some hot night's in Bakersfield.  You didn't run it long enough or hard enough to do real damage, especially if you're using synthetic oil. 

Link to comment
  • 6 months later...

Just wanted to give an update to the group on post effects from my summer bad day on the lake. Since the incident I did the following.

1. Immediately replaced the engine oil and filter.

2. Replaced the raw water impeller. 

3. Did a compression check. Everything was the same or within 1 psi of original.

4. Replaced hose clamp. 

Since then I have put approximately 50hrs on the boat with no problems. Still runs good and pulls as strong as ever. 

The one thing that has happened is the black paint has started to peel off the fiberglass muffler. As i suspect it saw significant heat during the over heat.  Since I have an FAE installed i am going to replace all the exhaust hoses and install the exhaust muffler pipes from FAE. All in all i feel lucky that no other damage was done.  

Thanks to all for replies earlier it helped relive some stress after the even.

Edited by dinovtx
  • Like 3
Link to comment
  • 4 weeks later...

Me still wonders why these $80-150k machines don't come with a $20  200 degree engine block alarm, I guess you still have to upgrade to a $10k Bayliner for one of those.. 

And why isn't a raw water flow sensor standard..? 

I find it appalling that the only thing measured is water temperature.. if you don't have flow no worries your boat surely won't overheat and you won't get an alarm either. It must be inside agreement with the service industry.. 

Moral of story watch for smoke that's your first clue to shut her down.. 

I know all you die-hard people will sit there and say you're supposed to look at it all the time.. but if you're jamming out distracted and listening to your loud engine or someone else is driving you for a set you can basically ruin your boat in the blink of an eye with no warning.. luckily OP @dinovtx was lucky! 

it is just mind-blowing that the most expensive boats in the industry don't have the cheapest if safety features to protect one of the most expensive parts of the boat.. 

Edited by The Hulk
Link to comment

FYI, the 2016 Indmar Raptor motors do have a sea water flow sensor.  The 2017-2018 Raptor motors, 2015 and newer Axis Challenger motors, and 2019 Malibu motors have exhaust manifold and/or exhaust pipe temperature sensors.  These features were likely added to help either prevent low water flow issues, or at least to make the boat operator aware of them when they occur.  Why do the previous Monsoon engines, like the 5.7L, not have these features?  I don't know for sure, but it seems like they haven't made any significant changes to those engines over the last decade, and that might have something to do with it.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...