I have a Snapper LT200 that my neighbor gave me when the clutch was worn out. I have since fixed that and used it for two seasons. The following is a short saga you can skip to get to my problem.
The battery had been dying and I had been charging it every so often. I replace the alternator. When I started it, it ran rough with little power. I drove around the yard and then parked it and put out the fire-the paint on the muffler guard caught fire. I then tried to start it again and it backfired. I pulled the flywheel and replaced the key. I checked the mag spacing and I replaced the spark plugs. One was so fouled it wouldn't fire-which led to the actual fire. I then removed and thoroughly cleaned the carb and replaced the gasket. The compressions are about 160 in each cylinder. I get a spark on both sides. The fuel pump works but I don't know what it's output should be.
My problem is that when I start the mower, it runs at high speed for about 5 seconds and then it slows. I can throttle it down but then only throttle it back up about half way before it runs rough and smokes. After about 30 seconds I shut it down and the plugs are fouled again. Usually on one side but not the same side each time. A flaky black foul that is easily brushed away. I get the same results when I try it with the air filter removed.
What should I try next.
Other info: Engine Model 406577 and Nikki carb 796110 with the throttle and choke inline.
