Originally Posted by Wayne 55
Simply by shutting off the fuel you are leaning the engine. Less fuel to ignite by a already weak spark. This is my theory to your problem. Now I am not sure where you are getting fuel that has no ethanol? Not saying it is not impossible but for the life of me I can not find it. The main reason ethanol is such a pain is simply it absorbs moisture from humid air. but unlike isopropyl (dry gas) it does not atomize the water to allow it to be burned off basically the water will sit on the bottom of the fuel tank. It also plays havoc with corrosion of Aluminum carburetors corroding them then simply plugging off the journals which gives everyone head aches when spring rolls around and nothing runs right. Anyone who races and runs Alcohol as a fuel 99% of the time Purges their engine with gasoline to eliminate the problems caused by the Alcohol. The engines today or should I at times say owners are not quite advised about properly caring for engines running ethanol. It's a huge learning curve.
There are a couple of local gas stations that advertise ethanol free gasoline, and just about all of the stations around here advertise their premium gas as as containing no ethanol. These fuels are what I usually run in my mower, but if I ever get it running correctly again, I'll probably also use an addition additive pretty regularly in hopes of helping keep the fuel system in top shape.
I mainly wanted to revive this thread since the grass is starting to grow and I haven't touched my mower and addressed it's rough running problem since December. The last thing I checked was pulling each of the plugs with the mower running, and not being able to tell a difference.
The first thing I'm going to have to do is drain all the gas, and then start taking stuff off so that I can access the coils and the carb.