Well I may as while add my 2 cents. I was reading about flywheel mag ignitions on various engines, like leaf blowers. I read where the ignition on my MB290 leaf blower has built in advance even though it had a flywheel mag. I hooked up a sears DC timing light and ran the engine at various RPM,s. Sure enough it did have spark advance. Took a photo even when running. That engine is at least 5 years old now and still rips. Also it will idle pretty slow. It did not want to start the other day. Took the carb apart & it was clean. But the pumping diaphragm was bad. Did not see it at first then took a real bright flashlight and shinned it on one side...and a bunch of tiny holes showed up on the other side. Very good way to check that way. Capt,n