Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Do you have a two cylinder engine? One cylinder may not be firing!
Run a cylinder test. Loosen the spark plug wires, and with engine running at idle, remove one wire at a time, engine should continue to run. If engine dies when one wire is removed, the opposite cylinder is not foring.
OK, but did you run the test when engine is bogging down? Or cold?
I'm thinking the engine has a weak coil on one cylinder, and is cutting out when hot. You can get a spark tester from auto supply and check the spark without removing wires. easier to test when it acts up.
I see question is still open, did you find problem?