Unknown oil leak

I recently have been running my tractor alot more than usual and i checked the oil when I got home I checked the oil and it was completely empty. I Had recently changed my oil so I checked my plug and everything was tight. No oil leaks around the motor. It doesn't burn any oil so the fact the it was empty is puzzling me. it is a older 11 horse briggs flathead. any idea on what it can be? Thanks

Is you want to pull the head and/or compression test it.

I would be betting its the bottom main seal.

Well- it had to go somewhere. Either leaking, burning, or both. So-

Top it up, take it for a good ride to get everything nicely warmed up, and park with the engine over a sheet of cardboard for several hours. Even let it run over the cardboard for 20 or 30 minutes, then leave it there overnight.

If it ain't leaking, it's burning. What grade of oil are you using?

Prob around bottom crank bearing.. Could be something as small as the governor.. Is it smoking? Oil can be sent into your carb and burned through your sump tank and you barely know it.

as far as I know it isn't burning so ill have to check the the seal. I used 10w 30.

Bottom crank seal, or ur carb is floating geting into oil making it look like nothing in it

xxXMowerdudeXxx wrote:

ur carb is floating geting into oil making it look like nothing in it

Please tell how you carb float could effect your oill.. im quiet interested.. if its running.. his carb isnt that high..

I had a 10hp briiggs dipstick ddint look like it had anything on it, pulled the drain plug i got over half a gallon of oil and fuel mix out...

hmm I did just rebuild the carb I will need to check that as well.

my 17.5 i think has a slight leak in the bottom seal... so who knows

Check the blowby and the dipstick my 12.5 has a leak on bottom also tighten the the oil drain

ok so I checked the seal and nothing. my thoughts are since it is an older motor (1986) and I have been running it so much that I may be burning oil in small amounts to where it is not visible but still, a whole quart in just a month??

might be getting past the piston rings. try pulling it aparts and making sure the rings are still good and the openings on the rings dont line up

Thecrazyoldcraftman wrote:

ok so I checked  the seal and nothing. my thoughts are since it is an older motor (1986) and  I have been running it so much that I may be burning oil in small amounts to where it is not visible but still, a whole quart in just a month??

dude a quart a months not that bad, i have a 12.5 that burns that in 3weeks, and i rarely see smoke, only comming off a high rev sometimes, or steep hills

The fact that it's older is certainly a contributing factor. Now- the reason I asked what grade oil you were using is because many factory owners manuals DO state that while 10W30 is preferable under certain temperature conditions, oil consumption will likely increase compared to the usually specified SAE30.

Top it up, and keep a closer eye on it.

I know it isn't That bad but I had the old oil in there for over 4 months and had the same amount in there when I dumped it so jumping from very little to no oil burn to a quart a month right after an iil change is a bit odd I believe.

Doc Sprocket wrote:

The fact that it's older is certainly a contributing factor. Now- the reason I asked what grade oil you were using is because many factory owners manuals DO state that while 10W30 is preferable under certain temperature conditions, oil consumption will likely increase compared to the usually specified SAE30.

Top it up, and keep a closer eye on it.

what temperature conditions does it say to use 10w30?

Torn from the page of the Briggs flatty single manual:

"Air cooled engines run hotter than automotive engines. Use of non-synthetic multi-viscosity oils (10W-30, ect) in ambient temperatures above 40F (4C) will result in high oil consuption. If multi-viscosity oil is used, check oil level more frequently to prevent engine damage due to lack of lubrication.

SAE30 oil, if used below 40F (4), will result in hard starting and possible engine damage due to inadequate lubrication."

Doc Sprocket wrote:

Torn from the page of the Briggs flatty single manual:

"Air cooled engines run hotter than automotive engines. Use of non-synthetic multi-viscosity oils (10W-30, ect) in ambient temperatures above 40F (4C) will result in high oil consuption. If multi-viscosity oil is used, check oil level more frequently to prevent engine damage due to lack of lubrication.

SAE30 oil, if used below 40F (4), will result in hard starting and possible engine damage due to inadequate lubrication."

oh well due to the fact I only use this in warm temps this might be the issue.