Ethanol vs. Outboard

[letsgosleddin]

I bought a 89 Wooldridge with a Yamaha 2stroke 3 cyl outboard jetdrive. The previous owner put a new power head on it. I guess the old one lost 2 cyls. My dad took the old power head to a boat shop and they couldntnt completely come up with why the cyls crapped out. One said possible over rev, and another it got to hot. Well if water is still coming out of the motor when its running like all outboards that means water is being pumped thru the engine. So I cant agree with over heat. I cant rule out over rev. Im not sure what pitch of impeller is in it now. Im guessing if the pitch is a few degrees lower than oem then yes it is possible to be over running the motor at full throttle. But would that heat score the cyls and in result make them loose all compression. The crank on the old power unit was nice and oily my dad said so the oil injection seems to be doing its job.

Would Ethanol be a contributor to this?

Any help or ideas would be awesome.

I am deployed to Afghaninstan so I havnt been able to tinker with it yet!! Got my Dad lookin after it..

Thanks Fellas.

[BigGoonTuna]

could be ethanol, bad fuel, or lean condition from running with blocked jets.  most yamahas have a rev limiter, and a temp and oil level sensor that will kick the motor into "safety mode" where it won't go faster than an idle if it gets too hot or you run the tank out of oil.

overheating is possible though, if some of the cooling passages had become obstructed with salt buildup or something like that.

ethanol primarily becomes a problem when the fuel sits for long periods of time, especially in wet environments.  if you run your motor all the time it's not such a big deal.

[PolarBear]

I run only non ethanol in all my outboards and power equipment (saws, mowers, tillers, etc).  Not only will ethanol attract and absorb water/moisture but it will dissolve fiberglass fuel tanks and rubber and nylon fuel lines and hoses.  It can be really bad news for outboards.

[jeepasaurusrex]

I buy my fuel at stations found at www.pure-gas.org.

[MADMAX]

Bad chit
Kitsap guys go to Cenex in Poulsbo, for pure gas.

[RG]

A majority of the time problems like that are due to overheating.  They probably fixed the water pump problem when they did the rebuild so you won't be able to find a problem now.  I'm not too familiar with Yamaha outboards other than that I've worked on a few boats that had them and they run forever.  Keep track of the impellers, don't let them go more than a couple years or so without replacement.

[PBinWA]

I use Sta-bil Marine in all my small engines.  If you have to use Ethanol crap gas then it is a good idea to add in Sta-bil Marine to neutralize the Ethanol.

[bloodhound]

ethanol gas was cause any of that. but it will eat certain kinds of hoses, not the new updated ones. its possible that impeller stopped pumping water causing the over heat and the they didnt know it happened. but it should have sent off an alarm saying it was overheating. so unless they were just driving around with the alarm on i wouldnt think that was it. too lean of fuel could be the reason. there are ways on certain motors to remove the oil injection system so you can mix the oil/ gas yourself. if that pump system goes out while your on the water your f'ed. so always keep enough mixing oil in your boat to mix with your gas if that stop working.

[letsgosleddin]

Thanks guys for the itel. Once I get back home ill take it out and run it slow and see how the water pump and all is working. Ill double check the carb settings before I take it out to ensure they arent running lean. Last thing I want is to drop a cyl while fishin on the river. Bad Chit right there.

[Skillet]

It's been beat to death already, but everybody's right - ethanol wouldn't have anything to do with overheating.  Those 3 cyl yammies are bullet-proof, as long as they get cool water.  This one probably had some junk in the water pump pickup that restricted flow long enough to fry the powerhead.  FYI - just because the "tattletail" is pissing out water doesn't always mean you've got enough water to cool the powerhead at full power - it just means you've got enough to push water out that port.  Be religious about checking your water pump pickup if you're running in areas that have a lot of junk in the water. 

+1 on regularly checking/replacing your impeller!

[PolarBear]

Check the strength and temp of your pee stream.