Yamaha 50 hp gremlins

[Steviemac23]

My 87 50 HP Yamaha was running just great when I last ran it last fall. It started right up this spring but, has no power when the throttle is rolled on. Upon investigation I find the following: Top cylinder, not hitting, second cylinder hits sporadic, 3rd cylinder right on. Changed all plugs, no change. Fire at all three plugs. Now I can think of a lot of bad possibilities if indeed there is fire and fuel at each cylinder but cant believe engines can go this bad sitting over one season in the garage! I am fairly mechanically inclined but very little experience with the outboard world. Any suggestions would be greatly appreciated!

 

[JB]

Re: Yamaha 50 hp gremlins

Hi, Steviemac.<br /><br />Try squirting some fuel mix into the top carbs while the engine is misbehaving. If that gets it running you have a fuel problem.<br /><br />If that has no effect, check for spark being bypassed by shorts to the bonnet or other parts only when the bonnet is on.<br /><br />Good luck.

 

[cclemon]

Re: Yamaha 50 hp gremlins

Stevie,<br /><br />The engine should not have gone bad just sitting in the garage, but the carbs could have gummed up from the fuel sitting in them. The fuel can turn to varnish and gumm up your cards over the winter.