Yamaha 2009 25 hp engine trouble please help

loganlejeune

Recruit
Joined
Oct 9, 2012
Messages
5
2009 yamaha 25 smh 2 stroke performance problems
I have a 2009 yamaha 25 hp 2 stroke engine. the motor starts and idles fine, but when you get to about half throttle it bogs down and wont take off. It sounds to me like its getting to much gas, but while the throttle is maxed out and the engine is bogging if you pinch off the fuel line it suddenly takes off and runs fine for a few seconds and then boggs again. Ive cleaned the carberator and changed the fuel pump diagram, and adjusted the air intake valves changed plugs and fuel line. Anybody have any ideas of what could be wrong?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,877
Re: Yamaha 2009 25 hp engine trouble please help

never seen air intake valves on a 2 stroke

Check to make sure timing is advancing properly to spec
 
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