917 1977 sears

I have had this tractor for about 10 years and have kept it up as it has a bucket that comes in handy up here in the north it has an m52 Onan
The 1 cylinder is blowing oil and foils the plug after running for about 2-3 minutes.I dont have time or the know how to rebuild the engine.I have spent a pile on a new carb and a rebuilt starter, now it appears to be toast.
Has anyone had any experience in replacing the engine with a new one? What brand and how many hp? I am looking for a fairly easy transplant.

HI
SHOULD HAVE SEEN YOUR POST SOONER BUT SOMETIMES WE ARE SLOW, YOU CAN USE ALMOST ANY 2 CYL. ONAN, BF, BG, P216,218,220, P224, ON THE P224 YOU WOULD NEED TO SWAP YOUR OIL PAN ON TO IT, THE ONLY THING TO WATCH IS 1 1/8" PTO SHAFT SIZE, NO JD SHAFTS OR MOTORS WILL WORK, EVEN AN OPPOSED 16-18 HP. BRIGGS WILL FIT PERFECT, BRIGGS HAS A 1" PTO SHAFT, IF IT WAS NOT SO FAR I WOULD LIKE TO TRADE YOU AN ENGINE FOR THE N52.
HAVE A GOOD ONE
JIMMY
IN SOUTH GEORGIA

HI
ON SECOND THOUGHT A BIT OF ADVISE, I BOUGHT A SEARS SUBURBAN W/ A BG18 HP ENGINE THAT HAD OIL RUNNING OUT ONE MUFFLER, COMPRESSION CHECKED OK, ROTATED A COUPLE OF HOTTER SPARK PLUGS, REPLACED PLUG WIRE, KEPT RUNNING, GOT TEMP. UP, SMOKED LIKE A TRAIN FOR A WHILE BEGAN TO CLEAN OUT CYL, SMOKE GONE & RUNS WELL, WORTH A TRY, HOW FULL IS CRANKCASE ????
THANKS
JIMMY

I have checked and filled the crank case with 10w 30 It looks like gas may be ending up in the crank case. It is pretty runny when i went to change the oil.
I would love to get it back to running the way it used to.
Just not to sure where to start.
I am up in Thunder bay, Ontario --north of the Us border so a long drive to Georgia.
I change a head gasket on the 1 side when i checked the valves. It seems to have pretty good compression however i do not have a testor.

HI
IF YOU DON'T HAVE ACCESS TO A COMP. TESTER, USE YOUR FINGER OVER THE SPARK PLUG HOLE WHILE SPINNING THE MOTOR OVER IF IT HAS GOOD COMP. 90-100 LBS. YOU WILL NOT BE ABLE TO KEEP IT STOPPED UP.
WHILE DOING SO LAY THE SPARK PLUG ON TOP OF MOTOR WITH WIRE CONNECTED, (OPEN THE GAP WITH A KNIFE BLADE) SO A COIN WILL FIT IN GAP TO BE ABLE TO SEE IF YOU HAVE A GOOD SPARK ON THAT CYL. IF NOT ROTATE THE PLUG WIRES IN TOP OF THE COIL, COILS DO GET BAD ON ONE SIDE, IF YOU ARE WONDERING WHAT ALL THIS HAS TO DO WITH YOUR PROBLEM, IF A CYLINDER DOES NOT HAVE COMBUSTION PRESSURE TO KEEP OIL PUSHED BACK DOWN BY THE PISTON, OIL WILL SLIP UP BY THE RINGS AND ACTUALLY FILL THE CYL.WITH OIL, THAT IS WHAT MY ONAN WAS DOING, HAVE HEARD OF VALVE GUIDES WEARING ENOUGH TO GIVE THIS PROBLEM, OR MABY A PISTON OR RING PROBLEM. HAVE A PERSON IN YOUR NECK OF THE WOODS GOING TO DO SOME WATCH REPAIR FOR ME.
HANG IN THERE
JIMMY

Thanks Have to sit tight till it warms up a bit getting cold in my shed .I will be a detective and check the options