Yamaha 60, down on power

[Paul_Dublin]

Have a pair of Yamaha 60s.<br />One seems to be running smooth. Starts great and runs smooth, but seems to be down on power.<br /><br />It's sister motor can get the boat on a plane but this one can't (although it was ok last most of last year).<br /><br />I cleaned the carbs, added a new fuel pump and used a clean tank with fresh fuel.<br /><br />Compression is 115,115,120 so this seems ok.<br /><br />The only thing I'm can't check conclusively is the spark.<br />Apart from touching the spark off the block, is there a good way of testing it?<br />Is it possible to adjust the timing of the motor?<br /><br />Any other suggestions why it would be down on power?

 

[WillyBWright]

Re: Yamaha 60, down on power

I would't worry about timing unless you find loose linkages. Have a look at the sparkplugs. If any aren't firing, it'll be noticable. They should all have about the same deposits on them. Any significant varinces from plug to plug usually indicates a problem.<br /><br />You can check spark on a running motor with an inductive timing light. If the light flashes, the plug that the wire is connected to is firing.

 

[Paul_Dublin]

Re: Yamaha 60, down on power

It there a weak spark and a strong spark?<br /><br />Assuming spark is OK, what else could cause power drop?