Running with a clogged filter is starving the engine for air. This creates a rich mixture which will foul the plug. But this usually is a sooty deposit on the plug. Prolonged operation with a rich mixture and partially fouled plug can cause unburned gas to "wash" down between the piston rings and the cylinder walls to the crankcase. This causes two problems, first it washes the oil off of the cylinder wall that should be there for lubrication, causing premature ring and cylinder wear and second, it thins the oil in the crankcase making it lose viscosity and lurication properties. This diluted oil can also get past the rings and into the combustion chamber easier, which will foul and gum up the plug. Another situation that can cause the plug to foul, is tipping the mower upsidedown to clean it. The oil will run up into the cylinder and if left upsidedown long enough it will get past the rings
.....just my 2 cents
Post Reply
Watch this Post
