Craftsman ZTS 7500 w Briggs 31M977 motor 20hp single cylinder ohv

[nealjaguar]

mower was running perfect then as I went down an incline it started smoking worse than a fog machine, as soon as I leveled out it ran fine.
then as I go on any grade, worse down or with the left side lower it smokes, as soon as it is level it quits. I have changed the gasket at the oil filler, head gasket intake valve guide seal,reed valve in the intake.
Any help or suggestions are appreciated.
Thanks, Neal

 

[BlazNT]

Sound like way too much oil.

 

[nealjaguar]

Sound like way too much oil.

new briggs filter & 1.75 qt oil, right on the line,never over full, less than 150 hrs on mower

 

[BlazNT]

Im wondering if your rings are going out. What oil did you put in? Compression test would be next for me.

 

[nealjaguar]

Im wondering if your rings are going out. What oil did you put in? Compression test would be next for me.

compression very good hot or cold, runs perfect on level ground, 30 wt castrol oil.
I found the problem, after tearing the motor down and inspecting the rings, head, piston, etc, I was told the crankcase is under constant vacuum I changed the "O" ring in the oil filler cap (dipstick) it runs fine now,
I could find nothing wrong with the old O ring, pliable, no cracks.
Who could figure.
Thank for the responses, Neal