1993 -70

[boomer]

i have been having problems with my 70 yamaha.i took it to the lake last week and it worked fine for two days then my son took it out and when he came back it was not running right.he said it started to loose power and was very sluggish.I checked it out and it seemed that #3 was fouling.I switched coils and plugs and it did the same thing.I took it out and it seems to want to go but it bucks and looses power.A friend says it is sucking water into the cylinder.i need some help on this problem

[Ken]

boomer,
Do you see any evidence of water intrusion into that cylinder? If so, then hopefully all you have is a blown head gasket - relatively easy to replace, but you need a Yamaha shop manual to guide you along.
If you have no evidence of water intrusion into that cylinder, and it has been at least three years since last carb overhaul, then I would do one - that just might fix your problem.
Good luck,
Ken K

[boomer]

Thanks Ken.The carbs have never been done and it sits for most of the time.Could this be the problem as it seems to effect only one cylinder.Also i forgot to use a fuel stabilizer last time iput it into storage.

[Ken]

boomer,
Yeah, clogged up carbs are most likely your problem. Order a carb repair kit (boats.net, sponsor of this forum has good prices) and overhaul those carbs.
If that fuel w/o stabilizer was allowed to set for more than three months, I would drain the tank and get some fresh fuel.
Also, if those spark plugs are at least two years old, put in some new ones.
It's best to run the outboard at least once every week in the off season, but that's probably not practical where you are, so for storage, you need to follow the procedure in the owners manual - fog the motor, add stabilizer to tank, etc. If you do not have the owners manual, go to www.yamahapubs.com - you can order online for both the owners manual and shop manual.
Good luck,
Ken K