Ymaha 90 hp two stroke. Wont go above 4300 rpm.

T

TBTech24

Seaman
Joined
May 3, 2011
Messages
56
Ive tested the spark inspected the entire fuel system. Clean as a whistle. Ive ohm checked the coils, wires, and pretty much just have the stator and trigger to check next. but i dont have a peak volt meter or adapter. Is there any way to check stator and trigger without? The boat just seems to lag when getting up on plane and even trimmed out doesnt go above 4500 rpm. Help!
 
R

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Ymaha 90 hp two stroke. Wont go above 4300 rpm.

Same motor as mine. More likely not electrical. Sounds like you're losing power on one cylinder, could be dirty carb, bad spark plug, low compression on one cylinder, bad fuel pump causing raw fuel being sucked into one cylinder and causing fuel-wet condition. Take a close look at your spark plugs to get an idea what's going on, like wet-fuel fouled plug, heavy carbon, etc. Plugs should be a tan color, not oily, not wet. Better not keep running motor like it is, since the problem could be a plugged carb jet/lean fuel mixture/can damage motor like that! Good luck and let us know what you find!
 
T

TBTech24

Seaman
Joined
May 3, 2011
Messages
56
Re: Ymaha 90 hp two stroke. Wont go above 4300 rpm.

carbs are clean as a whistle pump is good as well compression check out across the board i ohmed out the electrical components but the trigger and the stator, the other components checked out according to the book. spark plugs looked normal as well. i need to find out how to check the trigger and stator for proper function. i think im loosing spark on a cylinder or timing is retarding
 
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