Hello guys, I got a very strange problem on a Yamaha F25. It has not been in use for a few years and I don't have any history of it.
The problem is that it doesn't has any power when exceeding about half throttle. It shakes a lot when exceeding half way of the throttle. Just like it is entering a rev limit mode. I have checked compression (174 psi on both cylinders) and changed spark plugs (they were black).
And the funny part of all this is that it doesn't matter which way I swap the spark plug wires. It runs well at low rpms and runs crap at high rpms no matter which way I connect the spark plug wires. Is it really supposed to be like that??
The problem is that it doesn't has any power when exceeding about half throttle. It shakes a lot when exceeding half way of the throttle. Just like it is entering a rev limit mode. I have checked compression (174 psi on both cylinders) and changed spark plugs (they were black).
And the funny part of all this is that it doesn't matter which way I swap the spark plug wires. It runs well at low rpms and runs crap at high rpms no matter which way I connect the spark plug wires. Is it really supposed to be like that??