no power running hot

[doman4]

We have a 2003 Supra Launch. It is running hot and has no power. What could the problem be? Is there something that might be plugged?

[lowdrag]

The first and easiest things to check would be the impeller and thermostat and water strainer if you have one. Also check the water hoses from the hull to the pump to make sure you have no obstructions.

[Water Dog]

Doman4, I know you had a problem sometime back with running hot & no power on your '03 Supra. I am experiencing the same problems and curious as to what you came up with? We did a river run this weekend and encountered areas of moss & weeds. Made a wakeboard run and engine temperature increased well above the normal 175ish mark and engine went to what I want to call limp mode/very little power. After idiling for a few minutes temp came back to normal range. Did this on several occassions. Checked intake line from bottom to impeller, pulled impeller, put thermostat in boilng water and it was wide open - however did not do a temperature check for accuracy. Pulled the outlet line off of water pump and seemed to be pumping. Any ideas, thought or suggestions would be welcomed...

[scootn112]

I have a Supra Launch 2003 with the same issues where I can't get any power. I did not notice if mine was running hot, but it was like this as soon as I pulled away from the dock. An interesting thing is if I put it in neutral and rev up the engine it sounds fine. It is just when it's in gear that I lose power.

Now I did find one thing that is a problem and I don't know if it is the full culprit, but it has to be fixed first before doing more diagnostics. The rubber tube that goes from the exhaust manifold to the muffler was cracked. This almost caused a fire on our boat because it was blowing directly on the carpet which melted and started smoking. We turned the engine off, let it cool, and had to be towed in.

I removed the tubes from both exhaust manifolds and will be replacing them. I'd recommend checking yours. Upon inspecting the inside of the tubes I could see where both of the tubes where starting to fail. The rubber on the inside of the tubes was bubbled the entire length of the tube.

[Water Dog]

Scoot, were these the manifold hoses on the front of manifold or rear, for them babys to melt your would have to be running very hot and total lack of water to manifolds. Just a guess but sounds like that is not the problem but the result of the problem. What else have you checked, i.e. impeller, obstructions, etc..?

I'm going to run without thermostat one quick run this week unless I can get my hands on a new one in the next day or two to see if I have any over heating loss of power issues. Process of ellimination - cold lake water in a hot engine block, yeah thats gotta be a good mix...

[scootn112]

I had one hole in the rubber tube that connects the manifold to the muffler, not the manifold itself. If the manifold had a hole in it I think the boat would be on the bottom of the lake because if it got that hot the boat would have caught on fire.

But, you are correct. After talking to a Skier's choice service representative and my mechanic I know it was an engine over heat issue. The tube failed due to exhaust over heat. The over heat must have occurred because of the impeller failing or the intake is clogged.

The lack of power either came from the lack of oxygen in the engine compartment due to the exhaust, or failed gaskets. I hope it was just the exhaust and lack of oxygen.

The moral of the story is to watch your temperature gauge, which unfortunately I did not do. I grew up on boats with outboard motors that never had this problem or had alarms to warn you.

The answer for having an alarm to warn you would be to have an exhaust over heat alarm. If you water intake fails, then a sensor for the cooling water would not register the heat soon enough.

[Water Dog]

Scoot, let me know what you came up with when you figure out what the problem/solution was...

[scootn112]

Will do. It's going into the shop next week.

[DKJBama92Mariah]

The answer for having an alarm to warn you would be to have an exhaust over heat alarm. If you water intake fails, then a sensor for the cooling water would not register the heat soon enough.

SOLUTION: Water PRESSURE gauge. They sell them for outboards, and you can just plumb it in after the raw water pump. I plan on adding this before next season. Will try take pics and write a tutorial with a parts list when I do it next spring.

Sounds like a bunch of 03 boats here. Your boats are getting older guys, you gotta keep a better eye on her. They don't take care of themselves.

[scootn112]

I take very good care of my boat, but I learned my lesson on watching the temperature gauge better. My boat is in excellent condition.

Until this boat I've always had outboard motors, which require a different type of monitoring & maintenance.

I had the impeller replaced and the boat serviced every spring and fall, and check items during the summer. I follow the service advise of my mechanic who is very good with inboards (& ski boats) Lack of experience with an inboard is my biggest battle.

This problem was not from a lack of maintenance rather it was from ignorance (not noticing/knowing to check the temp. gauge), and not knowing how to diagnose the problem when it presented itself.

Please be careful when making statements that we need to take care of our boats. That was not the issue in my case.

[Water Dog]

Pressure gauge would not of helped me in my case, had great pressure from impeller. Would have to gauge the impeller, the water pump the block, the manifold, etc... I’m a great gauge watcher, wife on the other hand, maybe not so good…
Took the boat out last night after disconnecting pretty much all water lines and flushing the entire system, pulling impeller and thermostat. Ran beautifully, temperature below 170, perfect. Somewhere I had picked up some weed, algae debris and it was causing blockage, over heating and limp mode.
Solution; I am adding an in-line hi-flow intake water filter
( http://www.skidim.com/prodinfo.asp?number=SHE18016 )
really surprised that is not part of factory install, since the intake grate is large enough to pass small foreign obstacles. Funny there is a filter already installed on the wake bag system…

[scootn112]

Turns out the impeller for the water intake was shredded. I wish there was a way of telling how/why, but there isn't.

Luckily there is not too much damage, but the computer says there was an overheat. Having to put on two new exhaust hoses, replace gaskets in the manifolds, and fix some peeling on the first part of the muffler. Obviously a new impeller.

Did not do this but just for others info my mechanic said not to even attempt to start the engine without an ample water supply. Not even to just turn it over to check if it will start!

[Water Dog]

http://www.pitstopmarine.com//images/120wp_lg.jpg

I don't know, maybe a water gauge not so bad idea...
I'm thinking even if you replace impeller every season, if you suck something through the intake grate at 3500 rpm it may take your impeller out regardless of how new it is? $35 bucks is a pretty inexpensive upgrade.
Winter project along with intake fresh water strainer...