Have a 26hp kohler loses power once I ge tinto grass seems to lose half power. Has compression 160 and 150 psi. Plugs have a good burn on them not black but nice and brown. The govener is working rite and I have sprayed either through the carb when it was bogging and the engine did not pick up. I also checked the pulleys on the deck all turn nice and free. It seems to have all the fuel it needs and the spark seems rite Iam totaly out of ideas. Iam a boat mechanic by trade so I feel comfortable turning wrenches on this . Any ideas would greatly apprciated!!

You might have sheared the flywheel key if you hit something hard. its usually under the flywheel bolt. they are made to shear off if you hit something really hard. it will run but not restart...

jm You might have sheared the flywheel key if you hit something hard. its usually under the flywheel bolt. they are made to shear off if you hit something really hard. it will run but not restart... jm

I thought about that or a loose or broken magnet under the flywheel. But the thing starts rite up and sounds good not missing at all. But it seems like when you put a load on the engine the engine almost dies. What it sounds like is you pull the throttle back on it. It doesnt miss it just boggs way down. Like it looses at least 50% power or more. Its like it needs the timing to be advanced. But isnt the timing fixed on those? I thought about that or a loose or broken magnet under the flywheel. But the thing starts rite up and sounds good not missing at all. But it seems like when you put a load on the engine the engine almost dies. What it sounds like is you pull the throttle back on it. It doesnt miss it just boggs way down. Like it looses at least 50% power or more. Its like it needs the timing to be advanced. But isnt the timing fixed on those?