Well, you'll know if it's the plugs when you change them.

A couple other things could cause your symptoms-
Lack of air-
Lack of fuel.
Are both those filters changed?
I'd forgotten how much a new air filter can affect power output. I swapped in a new one recently and the difference UNDER LOAD was just so apparent. They get dirty relatively slowly, and you just don't notice the gradual decrease in performance. It "seemed" the engine was running well. When I got into the thick, wet grass, it was like a new engine.

Ditto with a fuel filter.
Under load is when the governor opens up the throttle plate in the carb so that it can get more air and fuel.
IF either is restricted, performance suffers.

Well the first thing you need to do is post the engine model number so we know what engine we are talking about, 24 hp doesn't cut it.

I suspect it is a V twin Intek and you are running on one cylinder. IF so, the first thing I would do is pull the valve cover and make sure the pushrods, rocker arms, etc. are OK and working BUT since you say you adjusted the valves, I assume you have noticed it there was a problem there.

Next I would pull spark plugs and make sure BOTH pistons are going up and down.

IF all appears OK there, then I would suspect the "Kill Wire" harness. More on that if required.

Walt Conner

The model # is 446777 Type 0302E1

Since you were going to change out the plugs Sat., did that make a difference?

When you adjusted the valves, did you use the CORRECT procedure with the piston 1/4" ATDC?

I did adjust the valves with the piston 1/4" ATDC. I got tied up at work Sat. so I didn't get a chance to get back on it. I plan on changing them out this afternoon as soon as I get off work.