The engine # is ( 3611516501). I know the mower was made in 10/06 and sold in spring of 07. The model mower is XWF2700-60 Quad Loop . I say it's an EFI electronic fuel injected motor because I do not see a carb on it. I am leaning towards a coil going out because of the symptoms. Seems to start acting up after it warms up about 30 min. into cutting and the more strain or full cut or higher grass. It usually slows to about 1/2 throttle then speeds up to full throttle but does not hold 30 seconds then slows back down again. I hate to cut grass at 1/2 throttle or 1600 rpm. as I know that's hard on the engine. So far I have changed the fuel filter, cleaned air filter and tried no air filter momentarily, cleaned both spark plugs on one the tip was corroded cleaned that and pulled 1 spark plug at a time when running and each had an effect on engine speed so I think both cyls. are firing. Problem seems to arise when mower is at operating temp. and under load. It got so bad last time cutting the mower stopped problem seems to be getting worse with every use. I think I would like to get either a spark plug or a coil checker under load tester but do not know what brand is good.
