It's been this way for at least seven years... but my Lawnboy mower (Tecumseh 5.5HP engine) has burned oil since I got it (used). It's not so bad when the engine is cold, but after it gets warmed up (20 or 30 minutes) or if it is operated on even a modest incline or if it's operated with a real heavy load (chopping piles of leaves for example), huge clouds of blue smoke come out. Especially on moderate slopes, the smoke is so thick that if there's no breeze I have a hard time seeing. Huge thick coulds. It also blows a lot of smoke when it runs the gas tank dry and the engine runs rough for ten or fifteen seconds. (Almost like the engine is running for a while just on burnt oil! Is this even possible?)
There is no apparent oil leak onto the garage floor when it's sitting there.
Rate of consumption: about half a quart of oil for every gallon of gas. That means 3 quarts per summer, roughly.
If I let it run low it doesn't seem to burn oil as bad, but I like to keep it filled to the top of the range on the dipstick. Pretty much every time I use it, it burns half a pint, enough to take the level from the "full" to well below the "fill" line. The overall capacity is probably 1.5 pints.
Every spring it's hard to start and I replace the air filter and find the spark plug completely fouled so I replace it too. I also change the oil every spring. But otherwise it runs very reliably and has had no other engine maintenance.
Now it's been this way for 7 years and I've never done anything about it - mainly because it only costs a couple bucks a year just to put more oil in and another two bucks for a new spark plug. Is this an endemic problem with Tecumseh engines, is this a sign that it needs a ring job/rebuild, or is there some valve that's stuck that might cause this?
Tim.