Briggs Classic 35 smoking

Hello,

Another smoking Briggs engine I'm afraid. I've been through the basics. Air filter is clean, engine hasn't been tipped recently as far as I know. Removed the breather assembly to have a look and found a real puddle of oil. Cleaned this out and reassembled before giving the engine another run. I was hopeful that given a few minutes to burn off the oil I would be away. Unfortunately no such luck. The oily cloud I created got worse and worse and I've ended up with a puddle of oil on the top of the mower deck. Looking at it a certain amount of this appears to have come from the muffler, the rest from somewhere around the breather.

I've not taken it apart again but I'm willing to bet that the chamber behind the breather has another puddle of oil in it. What could be causing this? I've not found much online about this specific problem, lots of people give good advice if the mower has been tipped or the breather isn't functioning correctly but this doesn't appear to be the case. Also, my spark plug is staying clean, not coking up at all.

Any advice would be very much welcome!

Andy

 

Is the oil level correct, or is it overfull? Is the engine running at higher than normal speeds?

 

Oil level is full but not overfull. I believe it is running at normal speed, I have just replaced the diaphragm as it was hunting quite badly.

I'm not sure if it makes any difference but the smoking only starts after 20-30 secs of running.

 

Sounds like bad rings allowing excessive crankcase pressure to develop.

 

Sorry for extremely slow reply. My wife has been ill and we've been away as well. I've just taken the engine off the mower and started to take it apart, couldn't get the oil plug out but that didn't matter as it turns out since it practically poured out of the breather assembly! I'm going to strip it down and replace the rings, fingers crossed that will fix it.