#2 cyl prob Yamaha 90

[Budster]

Hi All<br /><br />Today I developed a power loss problem on my 2000 90hp yamaha 2 stroke. It happened quick - was idleing after a long run, went to give it gas and it seemed fuel starved. It will idle and run lower rpm's but that's it; no guts at all. I limped home, logged into iboats and after looking over the helpful info here, I have:<br /><br />1) tested compression - all good<br />2) checked spark - all showing spark<br />3) Removed carbs - removed bowl and top cap, sprayed with cleaner, all ports seems clear.<br />4) removed spark wires, one at a time, while idling and #2 is the culprit.<br /><br />Now what? Could the "Emergency starter valve" have something to do with it? Is it more likely something bad with the carb? Any other suggestions?<br /><br />Many thanks,<br />Bud

 

[JB]

Re: #2 cyl prob Yamaha 90

Howdy, Budster.<br /><br />That middle carb seems like the prime suspect after your troubleshooting.<br /><br />Does squirting a bit of premix into it while at idle cause it to pick up? That would confirm that it is fuel starved. If so a thorough cleaning is in order with attention to all jets and passages.<br /><br />Good luck.

 

[Capt Ken]

Re: #2 cyl prob Yamaha 90

Or it could be flooding and killing the spark. If you spray fuel in the carb and it does nothing. Take some needle nose pliers and pinch off the rubber fuel line and see if it starts firing.

 

[Budster]

Re: #2 cyl prob Yamaha 90

Problem solved! It turned out to be a defective spark plug. <br /><br />Great tip on misting the fuel oil mixture directly into the carb while running - thanks! Tried it - no change. Focused my attention to the fire side, swapped plugs with another cylinder, pulled boots while it was running, and problem moved. Cleaned plug really good, still no change and spark was showing. Ran to the store, new plug, problem solved.<br /><br />Many thanks to everyone here! I wonder how the dealer would have handled that one? I'll bet it wouldn't have fallen under the warranty. <br /><br />Now, anyone have any ideas on how to get the fuel smell out of my wifes perfume mister? <br /><br />Thanks again,<br />Bud