128 engine power loss
 

I had someone call me today wanting to sell me a 128. He said it runs really good but after mowing with it for 40-45 minutes it starts to loose power/bog down. He can let it sit for about 15 minutes and it will run good again for another 45 min. Then the same thing. Could this be a carb issue? Trash in the fuel lines?
I haven't seen it yet, just wanted to get an idea of what it could be.

I am thinking a sticky exhaust valve possibly. Gets hot and sticks then cools down and works till hot again...

I've had that happen but instead of lose power it just dies completly and you can't restart it for awhile. It was a bad coil

Thanks for the help, I think I will pass on this one as he wants to much but I will pass on the info so maybe he can fix it.

I would check coil.