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Engine dies when gunned

pickler

New member
"Hi. Have a newer Yamaha 60 hp

"Hi. Have a newer Yamaha 60 hp. 4 stroke engine. Was not running well so I took it to a marine repair place. They did a spark and compression test in front of me and compression was high and even on all cylinders. They also had spark jump on all. They suggested a carb. rebuild. I left it with them. Came back to get it and it now idled well, and if you slowly increased speed it was fine, but if you punched the throtle from a stand still, it dies instantly. Sometimes it stumbles really bad but stays running just enough not to die. They said I would have to live with it that way because they couldn't do anything more with it. They said they syn. and timed all the carbs ( in fact, they plugged the hoses in and showed me on there electronic gauge how it was syn. and timed and showed me a vacum "stumble" test on the carbs.) They said they also tried to play with needles to make it richer and so forth, but that also made no difference. They said they didn't know what else to do. So I took it home and bought a manual. It's trouble shoot section said to check these things. Compression and spark (which they did) and if it still acted up, then a carb. job, which they did. It then stated, "if still a problem, then check ignition." Since they did all the other things except the ignition, then I assume the problem is in that area. But what am I suppose to look for or test/change?? Any suggestions??"
 
Water in the fuel will do that

Water in the fuel will do that.It comes from condensation in the tank especially if boat is kept in the water. Do you have a water seperating filter?????
 
"Mercury 90hp - 1980 outboard,

"Mercury 90hp - 1980 outboard, runs fine at high speed, drop down to lower speeds fine, when accelerting back to higher speed - motor dies- prime bulb, idle for a while, try again, sometimes gets up to high speed - sometimes does not- any ideas? fuel line? condensation in gas tank? Bad gas?"
 
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