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Hoping someone has an idea what this might be, I've taken this engine off twice now, and down to the local mower shop for repair, still leaking once it warms up.

The first time they replaced the output shaft seal, the oil pump gasket, and the O ring on the oil dipstick tube, which is pretty much everything on the bottom of this motor.

Is definitely leaking underneath somewhere that it cant be seen. Motor is clean and bone dry with shrouds removed, nothing running down the sides.

It was ok a few mowings, then oil mostly around the output shaft, all over the electric mower deck clutch, pulleys, flying off in all directions. Pulled the motor off again and

could see the shaft seal was crooked in its seat and the rubber seal edge (in contact with the output shaft) was partially rolled under, partially not.

They replaced the seal again, pretty much the same thing happened again. I finished out the season with it last year, have to add oil every 3rd mowing or so.

Not taking it back to these folks, they're the biggest outfit in town, supposed to be good but since I didn't buy the mower from them, they put me on a back burner and

act like they really don't want to work on it.

Do not know what brand seal they are using, are some better than others? I'm no small engine mechanic, just a tinkerer

Can't feel any side play in the shaft, no sign of heat damage to seal.

Really want to fix this, have had this mower a lotta years and have gone all out to keep it in nice shape. details :

Is a John Deere STX38, 1991. Kohler CV12.5s spec# 1249 Runs great, no smoke, oil still pretty much yellow at the end of the season,

virtually no oil usage before this leak, hope someone can help, thanks..... Paul

Sounds to me like someone has to learn to install seals?? Unless they cracked the case some how or there is a deep grove in the crankshaft where the old seal ran.

Have them check to see if the oil return port is open. I had one where the port was plugged and the oil pressure would build, forcing the seal rupture.

Thanks for the replies. Figured I'd order a seal and have a go
at it myself. I've replaced a couple auto transmission rear seals
Figure it's probably similar. How difficult is it to check the oil
return port?

It is just a hole which you can blow out GENTLY ie not with the compressor set to 150psi line pressure, with compressed air.
Dirty oil sitting for a long while will block up the passage, which a reason why it is a good idea to change the oil at the end of the season and not wait till the beginning.
Make sure you clean the shaft really well and I wrap the shaft with glad warp to protect the seal lip from accidental damage via the sharp edge of the key way and lube the lip with vasalene just to be sure.

bertsmobile1 said:

Make sure you clean the shaft really well and I wrap the shaft with glad warp to protect the seal lip from accidental damage via the sharp edge of the key way and lube the lip with vasalene just to be sure.

Click to expand...

Never here of that glad warp, sounds like a good idea. Learn something new
Thanks

reynoldston said:

Never here of that glad warp, sounds like a good idea. Learn something new
Thanks

Click to expand...

Isn;t that ultimately why every one is here ?
The day I stop learning you will be welcome to stand in line and shovel dirt on my cofin.

bertsmobile1 said:

It is just a hole which you can blow out GENTLY ie not with the compressor set to 150psi line pressure, with compressed air.
Dirty oil sitting for a long while will block up the passage, which a reason why it is a good idea to change the oil at the end of the season and not wait till the beginning.
Make sure you clean the shaft really well and I wrap the shaft with glad warp to protect the seal lip from accidental damage via the sharp edge of the key way and lube the lip with vasalene just to be sure.

Click to expand...

Hey, thanks for the reply and info. I'll do the wrap and lube, makes perfect sense.
How do I find the oil return passage? Does it return to the oil filter housing or
somewhere else I can get to without dismantling the engine?
Thanks again, Paul

poravec said:

Hey, thanks for the reply and info. I'll do the wrap and lube, makes perfect sense.
How do I find the oil return passage? Does it return to the oil filter housing or
somewhere else I can get to without dismantling the engine?
Thanks again, Paul

Click to expand...

Update: Found and browsed the engine manual. Checked the crankcase vaccuum at high idle with my manometer and had
-6.4"wc to -6.8"wc at all RPM's. seems to rule out intake valve, rings, and breather according to what I read.
Picked up a new seal today, will carefully install next weekend i"m not working and post result, thanks for the advice
hope I don't botch it, lol wish me luck. Paul

When you remove the old seal, you will see a hole which will go directly into the crankcase. I push a stiff piece of wire through to make sure it is open.

http://www.kohlerengines.com/onlinecatalog/pdf/tp_2339_d.pdf engine service manual

Check your engine mount bolts & see if they are tight, if loose crankcase may be cracked.

mechanic mark said:

http://www.kohlerengines.com/onlinecatalog/pdf/tp_2339_d.pdf engine service manual

Check your engine mount bolts & see if they are tight, if loose crankcase may be cracked.

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Huh, the engine mount bolts came loose about 3 years ago. was making noise awhile there before I figured it out and retightened them.
will look close, just about have the engine ready to remove. Anywhere in particular I should pay attention to?
Thanks for the help, Paul

Rivets said:

When you remove the old seal, you will see a hole which will go directly into the crankcase. I push a stiff piece of wire through to make sure it is open.

Click to expand...

Thanks Rivets, will check. Just about have the engine ready to lift off the frame. Hoping to do this weekend, Thanks again... Paul