See if you can solve this one! Local outboard mechanics are stumped! - The Hull Truth

vbumleg · 06-25-2009, 09:12 AM

I have triple 300 HPDI on a Contender located in Michigan. So as you can imagine, come October the boat gets completely winterized and put away. I keep the boat in rack storage that is not heated.

The last two years I had the exact same problem on the 1st run of the boating season. The center engine gaskets are broken and spraying water which result in a power loss of approx. 5000. Well, last fall, I made sure to be at the boat with the head mechanic to make sure the winterizing was done correctly. Being that I was standing there, they over did it as far as prepping it for the cold. They let that 100 below stuff run through them motors for at least 5 minutes. You couldn't have done a better job.

Well guess what, yesterday I took the boat out for the first time this year and you guessed it, the center motor gaskets are pissing!

Please help me figure this out, I have the best of the best outboard mechanics stumped on why this is happening. The biggest problem is that my Yamaha cert. mechanic that I use and trust is busy until August!

Questions:

1. WHY?
2. How do I get in touch with the local Yamaha rep to discuss and resolve this?

Thank you,
Mike

A1 Outboard · 06-26-2009, 04:38 PM

I don't believe freezing is causing your problem, but I'm not sure what gasket is causing the leak. Your engine is self draining so it is not normally necessary to run any kind of antifreeze through the engine. If you will look through the Yamaha-Motor web site you will find a parts breakdown. Find the gasket that is leaking and let us know which one it is so we can better analyze the problem.
Normally the factory reps are scheduled by a call from the dealer. You may be able to speed things up by calling Yamaha Outboard Customer Relations at 866-894-1626.

vbumleg · 06-26-2009, 07:44 PM

Quote:

Originally Posted by A1 Outboard

I don't believe freezing is causing your problem, but I'm not sure what gasket is causing the leak. Your engine is self draining so it is not normally necessary to run any kind of antifreeze through the engine. If you will look through the Yamaha-Motor web site you will find a parts breakdown. Find the gasket that is leaking and let us know which one it is so we can better analyze the problem.
Normally the factory reps are scheduled by a call from the dealer. You may be able to speed things up by calling Yamaha Outboard Customer Relations at 866-894-1626.

After looking at the web site, I determined it is the crankcase cover gaskets. Someone mentioned that maybe the surface is warped and allowing water to be trapped inside.

I agree with you that these are self draining, but freezing is the only thing I can come up with. It has happened on the first run of the spring after being stored cold. Someone else mentioned that possibly they are drying out and cracking, that doesn't sound possible to me. What do you think?

A1 Outboard · 06-29-2009, 08:57 AM

I think the gasket you are talking about is cooling cavity for the crankcase which is only used on the 300. A cooler fuel mixture in the crankcase increases horsepower. This cavity gets its water supply from a small hose connected to the exhaust adapter which is under the powerhead. The water exits through another small hose into the midsection. It is possible that the exit is blocked or restricted causing water to remain in the cooling cavity. I would suggest that when you store the engine you remove both hoses and blow air into the cavity from both ends. You should also blow air into the fittings that the hoses connect to so they can be cleared. This should remove any residual water and prevent freezing.