# 13.5 HP Briggs and Stratton question



## moze229 (May 18, 2010)

Hello all! :wave:

I have a question for all the small engine experts out there. I'm not a mechanic by any means, but I've found my way in and out of engines before, mostly motorcycles. I just wanted to throw this out here to get some ideas/criticism before I start throwing parts at this thing.

This engine (13.5 HP I/C. Model - 28R707 Type - 1120-E1) is about seven years old, and is in a Craftsman lawn tractor. It's treated me well, but it's always seem to have been a loud runner for some reason. Recently, I've noticed that if I fill the crankcase oil to the regular operating level on the dipstick, I get a BBQ smoker - oil coated spark plug and lots of smoke. I believe the oil is coming from the crankcase breather tube and burned but I'm not 100% sure. There seems to be an excessive amount of oil inside the breather filter. If I let the engine just sit and run with the oil at operating range indicated on the dipstick - no smoke. But as soon as I put a load on it the smoke begins. (engaging blades, moving forward, etc.) Sometimes I can disengage the blades and the smoke will stop. However, if I have the oil just below the minimum operating range indicated on the dipstick, I have no problems with load or not. Of course, I'm not going to run this engine long term without the proper oil amount. 

The dipstick reservoir has not moved and the dipstick is the original, so I'm sure that's not the problem. I'm also checking the oil using the proper method indicated in the owner's manual. I did a crankcase vacuum test and it's pulling about 4" on my manometer so there doesn't seem to be an excessive pressure problem. As mentioned, I think excessive amounts of oil are coming from the breather tube, but I'm not sure why! I was going to immediately suspect a head gasket, but I'm not so sure. I don't think it would be a piston ring because this would cause a smoke situation no matter how much oil was in there. Is there some type of pcv-type valve that's stuck open? Any suggestions on things to check next would be greatly appreciated. This thing has me baffled.

Matt


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