fuel additive

[owen davis]

I have a 1987 150hp yamaha and have used a valvetec product called ring free as a fuel additive. The product is no longer available at the marine center I use. Is this additive advisable and if so is there a suitable alternative?

[sandflyer]

Owen...My 2 cents. We have been using Marvel Mystery oil for a very long time and no loss of compression due to stuck rings. It's a gum base solvent and is available from Wal Mart. Directions are on the bottle and it's added to the gasoline.

[Ken]

Owen,
I think most Yamaha owners use either Yamaha Ring Free or a product called SeaFoam - both very strong detergents.
I personally use SeaFoam - every third tank at a ratio of 1 oz to 1 gallon.
Both products are suppose to keep carbon buildup at bay and also keep the fuel system clean.
Good luck [img]smile.gif[/img] ,
Ken K

[sandflyer]

Ken, Any concern with using seafoam in an older fuel system i.e. loosening up crude within the tank.

[Ken]

sandflyer,
Your onboard (local) filter should catch any debris - I think it is probably around 20 micron.
But you really need a 10 micron fuel filter/water separator in the fuel line in addition to the local filter.
Yamaha came out with a service bulletin recently advising such a filter to counter the effects of ethanol blended fuel that we will all be burning in the near future. Evidently ethanol can break down deposits in the fuel system that gasoline and detergents can't .
Take a look at this link for the effects of ethanol:

http://www.boatus.com/news/e10_0706.htm

Good luck [img]smile.gif[/img] ,
Ken K

[IFish4Tuna]

Sandflyer - I'm no expert on this, but I used to squirt a bit of mystery oil into my pistons and crank w/ out plugs in for winter storage. A few years back a mechanic recognized I did it when he was prepping my boat for the season. He recommended against it because he claimed the material does not compress, and that it could force a head to crack on start up. I don't know if that's B.S. or not. Just passing along an urban legend.

Dunno if others have any info on that.

Ed