Old 11HP Briggs rebuild

Forum newb. I found an old 400cc , 11hp Briggs bottom shaft engine in a junk yard. Fairly complete , missing air cleaner assembly and starter. It does turn over , but when tipped on its side , a lot of water came out of the carburetor.

Im sure i could just clean out the carburetor, change the oil and go .. but i dont know this engine, could burn oil or knock. I picked it up because i wanted a winter project. So im planning a complete tear down , inspection and rebuild.
I went to the local outdoor center , in search of a gasket / seal set , and rings, spark plug , carb kit ect.. counter drone looked at me like i was stupid , for messing with that old of a motor. Tried to sell me a used $300 motor. I literally got no service , i ended up walking out. Figured I'd buy online.

Where is everyone buying rebuild kits for these old motors?
I search the model number and a lot of interchangeable crap like spark plugs , fuel line and filters come up.

Its a 252707 model , 0645-01 type ,84100511 code .

I assume its a 1984 ?

Any help would be appreciated! Ill post pictures of the engine when ever i figure it out. Thanks !

Yes it is a 1984 25 cubic inch. I run the same engine on my mower. I would think eBay is your best shot.

I rebuild a lot of small engines and I usually don't have to buy any gasket kits. If I do buy something it usually is the rubber seals to seal the crankshaft or head gaskets only. All other gaskets can be made using a cereal box type cardboard. As for rings, as long as there is tension on them when placed in the bore they will seal the piston, just clean them with a file or sandpaper to remove sharp edges. Anything else wouldn't be worth buying new because the individual part will cost more then the motor is worth like piston, rod, crank, and cam. This is where a parts motor comes in handy.

If you wanted a little more performance, put a stock rod from a briggs OHV in it. more lift for more power. And if you really wanted power, port and remove the eyebrows. But thats later.......

I also run an 11 horse flatty on my rat rod mower, probably the best running motor I own. Definitely a great little engine.

i too have a 1983 briggs 11hp, unfortunately it bit the dust. I think CraftsmanQuad19 started a build thread on it called the hh11 or something like that. it had over 30000 hours on it, so it was time for it to go. it earned its keep

My favourite is the non-syncro balanced 8-11hp Briggs. They're just so lovely to hear running. Any engine I mod/take apart I usually take the balancers out because they create a bit of drag and are liable to crack/break at high rpms. The only downside is the engine does not run as smooth but it isn't really noticeable.

Yah, those old 11hp engines are strong enough to move a tank, LOL, well a small one anyways.

Yeah I think those older smaller engines are understated and underused in the offroad/mower modding community.