I have a sears lawn tractor, has worked fine most of the time, but now it is cycling through something: I was mowing, and suddenly lost power, and it almost turned off, but then it ramped up to full throttle, and kept this cycle up. I checked the fuel, plenty available. Checked oil, fine.

I started it again, without load, does the same thing, ramps up, down, up, down.

Where do I go from here?

I changed the fuel filter last year; could the fuel supply cause this? Someone mentioned a malfunction with the "governor"? (what is a governor, where do I find it, what do I do? Diagrams anyone?)

Thank you for your help.

Clean the carb, check the linkages, check the air filter.