1990 50 hp yamaha jet power problem

charlie boswell

Recruit
Joined
Oct 25, 2008
Messages
1
I have a 1990 50 hp yamaha jet, 110 psi top 2 cyls 105 on bottom, carbs cleaned, new plugs and gapped, strong spark on all 3 cyls, idles ok, boggy out of the hole, +_ 3000 rpm @ full throttle and jerky. while @ idle pull top 2 plug wires and motor sputters, but when i pull the bottom plug wire, no change in idle, if i put the middle plug wire on the bottom cyl plug while idling, same no change in idle.i put all plug wires back right then i sprayed fuel in the bottom carb while idleing, still little chang actually only bogs slightly. the last thing i can think it may be is the ignition module on the side of the motor, but new one is $500. expensive. can i have this module tested somehow, or does anyone have any other ideas? thanks
 

yamamarinetech40

Petty Officer 1st Class
Joined
Dec 17, 2006
Messages
328
Re: 1990 50 hp yamaha jet power problem

Describe to me in detail how carbs were cleaned....and don't put one plug wire on another cylinder and don't keep trying to run it up when it doesn't want to or you'll have a piston that you can look through....it's the carbs.
 
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