I still have the problem and it seems to be getting worse little by little. Just so you know, the mower has only 170 hours on it, it's stored indoors when not in use and it's only used about 2.5 hours per week at my house.
Here's what I've done so far.
- Checked condition of plugs. They look clean, no black and not fowled. Look great to me. They were new as of this spring anyway.
- Checked flow of fuel by disconnecting the line that goes to the carb and put a hose on the fuel pump on that outlet. Started engine and fuel flows quickly out of the hose.
- Checked fuel filter (blew through it and it looks clean - it was replaced this Spring)
- Checked/cleaned air filters (they were new as of spring too)
I've been using premium gas. I ran a couple cans of fuel system cleaner through the gas too after this problem came about. No help.
Do you think the carburetor is dirty inside? Could that be it? Would it be worth the trouble to take it apart and clean it out (remove the bowl, jets and spray it with carb cleaner). I hate to take it apart if I don't have to though.
The governor seems to work fine. The engine speeds up when under a load like if you take off quickly or start up a hill from a stop...you'll hear the engine kick up in speed.
This couldn't be electrical could it? The way it's acting, it seems more like a fuel issue (carburetor dirty?).
In the past I could engage the blades at half throttle, which is what I think you're supposed to do anyway to be easier on the electric clutch, etc....but now, if I don't have it at full throttle it'll nearly kill the engine when I engage the blades. Even at full throttle, when I engage the blades, the engine slows down and sputters like crazy, running really rough until the blades are up to speed. Then when I start mowing, if I run into some thicker grass and I'm going 3/4 speed or so, it'll start sputtering like crazy again until I slow down so it's not under so much load. Basically, a heavy load is what triggers the problem. Otherwise the engine runs really smooth and sounds great.