gas with ethanol

**NITE BITE** · 03-12-2012, 06:41 PM

Just bought boat with 150 horse out board motor, was advised not to run any gas with ethanol threw the engine.
They said that it could cause motor damage is this true? Any info would be great the motor is two stroke mix 50 . 1 yamaha 1999.

**ebijack** · 03-12-2012, 06:52 PM

Anything higher than 10% can harm some of the rubber diaphrams hoses etc. Other than that, I wouldn't worry about it. I run a 1996 150 yami and have not had any problems. The Gov. is pushing for 15% which won't hurt newer vehicles but will kill all older boats. Inboards and out boards. We'll have to start running an additive when that happens.

**ReelTime** · 03-12-2012, 08:20 PM

There are additives that you can run in your fuel to help with the effects of the ethenol. I run the 10% junk in my 02 yamaha outboard and have no problems. I mostly use the starbrite additive called Star Tron.

**Throttles Down** · 03-13-2012, 07:02 PM

I have twin Yamaha 150s 1999 OX66s and have not had any fuel related problems. Just make sure you have a good fuel/water separator in your system and drain it regularly ,Yamaha recommends a 10 micron filter. I also use stabil marine fuel treatment [the blue stuff] . If you replace your low pressure fuel pumps I would recommend you get them from Yamaha as I believe it is one of the up dates for these motors, was told that the after market ones don't hold up as well to ethanol. I just reread your post and see you just bought it. Its recommended that you replace or rebuild the low pressure fuel pumps every 4 years. If you get a hole in the pump diaphragm, fuel will enter the crank case and detonate [not a good thing] other than that these motors have a reputation as one of Yamaha's most bullet proof motors
congratulations on your new boat

Don M