Sounds like you are taking a good systematic approacg at it.
1, I suggest to drain all the crappy oil, get Castrol or Doo oil. I personally run Doo Mineral for 15 years, no problem with it, ever.
That will rule the oil out. Crappy oil can cause VERY weird things. Bad oil can take the power out of the gas, causing the inability to rev
2, I wold confirm the setting of your oil injector pump. There is 2 marks on the lever, and one on the case. The case mark should be between the 2 arm marks. I line mine up just above the lower mark. To much oil will foul a plug FAST. Have a bud who insists on running his Yammi MX bike 32:1. He goes through 2 plugs in a days riding, allways. I tell him to lean the oil, he never listens.
3, the box that splits the fuel, is the fuel pump. That might be going bad too. A low flowing pump will starve the engine of fuel, but the oil will still be pumping into the engine cause they are 2 separate pumping systems.
4, could be weak coils. You say that it's worse at a lower plug gap. Lower gap is easier for the coil to "jump" the gap, but is acctualy harder on the coil, becaause a smaller gap can draw more current from the coil. Larger gap, the coil has to build more voltage to jump the gap, and in essence uses less current. This will cause less heat in the coil, letting it acctually produce spark longer.
Just some ramblings off the top of my head to check. Sleds are not to much different than HD engines. Fuel, air, spark. They all need those three things. Fouling plugs is usually oil or weak spark, in 2 and 4 stroke engines
1, I suggest to drain all the crappy oil, get Castrol or Doo oil. I personally run Doo Mineral for 15 years, no problem with it, ever.
That will rule the oil out. Crappy oil can cause VERY weird things. Bad oil can take the power out of the gas, causing the inability to rev
2, I wold confirm the setting of your oil injector pump. There is 2 marks on the lever, and one on the case. The case mark should be between the 2 arm marks. I line mine up just above the lower mark. To much oil will foul a plug FAST. Have a bud who insists on running his Yammi MX bike 32:1. He goes through 2 plugs in a days riding, allways. I tell him to lean the oil, he never listens.
3, the box that splits the fuel, is the fuel pump. That might be going bad too. A low flowing pump will starve the engine of fuel, but the oil will still be pumping into the engine cause they are 2 separate pumping systems.
4, could be weak coils. You say that it's worse at a lower plug gap. Lower gap is easier for the coil to "jump" the gap, but is acctualy harder on the coil, becaause a smaller gap can draw more current from the coil. Larger gap, the coil has to build more voltage to jump the gap, and in essence uses less current. This will cause less heat in the coil, letting it acctually produce spark longer.
Just some ramblings off the top of my head to check. Sleds are not to much different than HD engines. Fuel, air, spark. They all need those three things. Fouling plugs is usually oil or weak spark, in 2 and 4 stroke engines
