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Engine Overheating Problem


ALWAYSPDG

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Hey guys, need your help again! Here's the info:

2001 Malibu 23' LSV with Monsoon engine. EFI

I have recently noticed a overheating problem with the engine. I fire up the engine and all is good. I idle out past the no wake zone and all is good. Engine temp is around 160 to 180. I then bring up the power and start cruising at around 20 to 25 MPH and the engine temp starts to climb! It will be around 220 or even at times 240 MAX temp on the gauge. Surprised.gif

The boat has been in the lake/water since early May of this year. There has been some plant growth around the water line and also the wood tail step (at the back of the boat) has shown a lot of growth over the last month.

I am just thinking maybe the water intake grate is getting clogged from plant growth on the bottom of the boat. And, no I haven't taken the boat out of the water yet to see if this is the case yet, I plan on doing that this Friday.

One mechanic thought it was possibly the impeller.

DO YOU GUYS HAVE ANY IDEAS WHAT MIGHT BE CAUSING THE HIGH ENGINE TEMPS??????????????????? Dontknow.gif

The impeller was replaced mid year last year by the previous owner. The previous owner owned the boat for three years and each year he had the impeller replaced as part of his maintenance program.

Thanks for the help,

Mike Cry.gif

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Things to check, not necessarily in order:

1. Impeller

2. Hoses for blockages, usually at the tranny cooler

3. Thermostat (may not be opening completely) - do not replace with an automotive type, get one from the Bu dealer

The fact that it doesn't heat up under idle would indicate to me a partial obstruction somewhere, & not a complete failure of the impeller or thermostat.

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I have the same boat ... Is the rev limiter kicking in when it overheats? Is the gauge reading a steady temp or is the needle bouncing around a bit?

The reason I ask is because earlier this season I thought my boat was overheating, but it sure didn't seem like it. The rev limiter wasn't kicking in, and the engine just didn't seem to be that hot. Turns out it was the cannon plug giving me problems. I unplugged it, plugged it back in, and I've been good ever since.

Of course, check everything that Wakegirl mentioned as well.

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every now and then I get weeds stuck in my tranny cooler. Just undo the hose and stick your finger up into the bottom of it and scrape the crud off. Thats the first thing I'd check. The other 2 tracie mentioned are also very key.

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I have seen the impeller look fine but the blades won't pump enough water at more than very low rpm. It is like hydroplaning. I ended up reversing the impeller to end the day. It worked fine but ordered a new one and replaced it would never trust it for long.

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When was the last time you changed the impeller ? if it's been a couple years or even 1 season depending on how you run your boat that might be the problem.

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I have the same boat ... Is the rev limiter kicking in when it overheats? Is the gauge reading a steady temp or is the needle bouncing around a bit?

The reason I ask is because earlier this season I thought my boat was overheating, but it sure didn't seem like it. The rev limiter wasn't kicking in, and the engine just didn't seem to be that hot. Turns out it was the cannon plug giving me problems. I unplugged it, plugged it back in, and I've been good ever since.

Of course, check everything that Wakegirl mentioned as well.

Jeff,

Are you talking about limp mode? I've never heard of the rev limiter coming on from overheating, since that's tied to rpms that doesn't make sense to me. (But I may just be having a blond moment too, you never can tell. :))

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I have the same boat ... Is the rev limiter kicking in when it overheats? Is the gauge reading a steady temp or is the needle bouncing around a bit?

No, the rev limiter has never kicked in! And YES, the temp guage does move around a little bit, the needle bounces around about 1/8".

Thanks, Mike

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When was the last time you changed the impeller ? if it's been a couple years or even 1 season depending on how you run your boat that might be the problem.

The impeller was replaced last season by the previous owner. And I would say it was repalced April of 2007. So, it may have two seasons on it at this point. This is a guess, but it might have 40 hours on it at this point.

Mike

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I have the same boat ... Is the rev limiter kicking in when it overheats? Is the gauge reading a steady temp or is the needle bouncing around a bit?

The reason I ask is because earlier this season I thought my boat was overheating, but it sure didn't seem like it. The rev limiter wasn't kicking in, and the engine just didn't seem to be that hot. Turns out it was the cannon plug giving me problems. I unplugged it, plugged it back in, and I've been good ever since.

Of course, check everything that Wakegirl mentioned as well.

Jeff,

Are you talking about limp mode? I've never heard of the rev limiter coming on from overheating, since that's tied to rpms that doesn't make sense to me. (But I may just be having a blond moment too, you never can tell. :))

hehe ... Yep, you're right. Limp mode is what I meant!

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Where exactly is the cannon plug located?

I suspect that it is an electrical connector?

Mike

Yeah, it's an electrical connector. If you open your engine hatch, it's covered by a black rubber boot that plugs into a plastic-covered square, maybe 8 inches by 8 inches. It's bow-side of the engine.

It's worth trying. I've seen my boat legitimately overheat before when my impeller went out a few years ago. I just remember opening the engine hatch at that time and feeling the heat radiate at me. This spring when the gauge started showing that it was overheating, I didn't feel the same thing. And I was able to run the engine to high RPMs without it being limited. The gauge bouncing should have tipped me off right off the bat, but I went ahead and replaced the thermostat twice to no avail before someone recommended that I check the cannon plug. I unplugged it, plugged it back in, gave it a twist, and it was good to go.

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I have the same boat and engine. This summer I had the same issue. The solution was replacing the impeller and gasket.

When I looked at the original impeller and gasket they looked fine. After checking all the other usual suspects I hooked up the flush pro and everything ran well. Went to the lake and the same issue. Flush pro will allow the pressure of the hose push water through the engine and mask the problem.

After calling Discount Inboard Marine they gave me the clue. Take out the current impeller and gasket, through them away! Looks are deceiving. Replace with new parts and put your disconnected water intake hose in a bucket of water. Fire up the Monsoon. The impeller should draw water out of the bucket and through the engine. (something like 5 gallons in 15 seconds at 3000 rpm) If that happens finish up and go to the lake and have fun.

dlb

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I will try disconnecting the cannon plug and reconnecting it and clean it with a electrical plug spray cleaner too, while it is disconnected. I am also going to look at the bottom of the boat and see if the water intake grate is clogged. I am also going to look at the inside of the water hoses for debris inside the hose.

I am also bringing up a brand new impeller with gasket and also a thermostat with gasket just in case.

Thanks for the heads up on the connector issue!

Mike

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