first, check the bolts that hold case together, they will, and do come loose.
I replaced that gasket by removing the engine pulley, turning engine upside down, and lifting off the bottom case cover, unless i am forgetting something, everything stays in the main part of engine, but i would wait on another response here.
Oh, and that gasket, also comes in different thickness, the thickness of the gasket determines crankshaft end play.

johninmd, thanks for your reply.
Here is engine data:
Model 252707
Type 0669-02
Code 85061210

Seems the lower main crankshaft seal leaks too. The top of the drive belt pulley (upper)has oil in it after sitting overnight after the day of mowing. It slings oil on the floor when you turn the key. It loses about 4-5oz in 2.5 -3 hrs of mowing. Makes a mess in the garage when you start it up the next time.

Hope to hear from Walt.

Thanks,
Marshall

Well I am no Walt, I knew Walt, and I sir, am no Walt.
After getting the pullies off, and the engine off the
tractor, turn it upside down and take the bolts out of the
bottom, and remove the bottom cover.
You will need to remove all of the old gasket material,
and since you have used 10-40, you will notice a lot of
dark brown crud everywhere, so you might need to rinse that
out with straight gas as well, the seal will be easy to pluck out as well.
Just re-assemble, and never, ever, use 10w40 in an air
cooled engine. Just straight 30 w

Fish

I'd suggest going to the Briggs site and downloading the IPL for your engine. (see link)
It has some exploded parts drawings and the correct part#'s.
Do check the bolt tightness and snug up if loose.
Then check the crankshaft end play. This will help you determine if you want a "thinner" crankcase gasket. They come in .015, .009 & .005" thick.

Here is a link that might be useful: Briggs IPL

i bought a gasket kit online for mine once, only cost about 12.00 or so. has several bottom end gaskets in it, and also a crank seal. But dont ask, it was like a couple years ago and i have no idea now where i got it now.

Crankshaft seals do not typically come with a gasket set. I suggest you try your local NAPA Auto parts dealer, may take them a day to get the gaskets and seal. You MAY be able to get the sump gasket separate. I would go for a .009" thick. End play should be at least .002", that is about the amount you can feel when push/pulling.

I would only add a couple of things to what has been said. I would drain the oil first thing and clean the area around the lower crankshaft, the 3/8" or so before the step down so that the sump can slide off the crankshaft without binding in the bottom bearing with possible damage if forced. I use 400 wet/dry sand paper.

When you have the sump off, check the mounting hole in the oil slinger. That old an engine may have elongated the mounting hole. If this gets too bad, the oil slinger/governor starts stripping/jumping teeth.

Torque for sump bolts is 140 inch lbs. No sealant is required nor recommended for the sump gasket but because sump gasket failure is a common problem with most B&S vertical shaft engines, 10 hp and up, I use Copper Coat.

Try to get the new seal in evenly all the way around, coat it with oil or grease between the double lips, assuming it has double seal lips.

Walt Conner
wconner5 at verizon dot net