Kohler Magnum M20S PTO shaft size
 

It has always been my understanding that the M20 had a 1 1/4" PTO shaft size, which was an odd ball and took a special (much more expensive) PTO clutch. I've discovered the one I have that came out of a Cub Cadet 2082 originally has a 1 1/8" PTO shaft just like my M18 does. Are there some out there that were 1 1/8", or is mine an odd ball somehow with a non Cub Cadet engine/crankshaft in it? Or do I have an M18 masquerading with an M20 ID tag, and M20 decals on the engine tins?

:bigthink:

I have a 2082. I will try and find an easy way to check it. Might be a few days or weeks, it is too hot outside to do anything here in Tennessee.

Don’t go tearing stuff apart to see. It’s more of a curiosity than necessity. With that being said you might be able to tell by taking the bolt off that threads into the shaft.

I have two 2072's, both have 1.250" shafts.

Thanks, if Roland were still here he would probably have solved this by now.

I found some interesting info, I'm going to dig out my calipers and go check both of my engines. Maybe it's not engine specific but Cub model/size specific, According to this below, the Supers with Magnums used 1 1/4" and non supers (KT and Mag) used 1 1/8". I never actually measured mine, but I ASSUMED the M18 would have been 1 1/8" because I've never had one that wasn't, and this one came off a 1711 repower. I just know my PTO clutch fits both of them. See below:

Warner Front Electric Complete PTO Assembly 1 1/4 inch shaft P/N 717-3043 USE 917-3043 Fits 1872, 2072, 2082

Warner Front Electric PTO Assembly W/ Spacer #1 1 1/8 in. crank
P/N IH-144720-C91, 717-3003, 717-3044, 717-3038 Fits 682, 782, 784, 1872, 2072, 1050, 1204, 1210, 1211, 1282, 1535, 1541, 1710, 1711, 1712, 1806, 1810, 1811, 1860, 1862, 1882

I just confirmed both of my engines, the M18 and M20 are 1.125” shafts. Both came off Cub Cadet tractors too.
:bigthink:

Attachment 113613

Attachment 113614

According to the Kohler Parts Manual I have for M18 & M20 engines,
The Spec Number shown in The Grinch's photo (49512) show a Variation Number 0f 93.
That Variation Number in the grid for crankshafts declares that it should be
1 1/4 dia x2 23/32 (tapped pto) p/n 52 014 71

So I guess the next logical question is what are the spec nos. on your engines?

Me thinks you have a case of a duck dressed up as a swan:biggrin2:

My spec on the M20 is 49584. I’ll look for the M18 one next time I’m out in the shed, but that one is “normal” as far as the shaft size goes.

Attachment 113617

Hehehe. Thanks for that.

I found a post on another thread here, Roland said “The 2082 (141-731 & 142-732) rolled out of the Factory with a Kohler M20-49584 Engine in it.”

So, I may have the duck dressed up as a swan. That kind of sucks. It looks like that should be the same crank part number as Ironman’s post above shows. Is there any other identifying factors with these engines. I think I remember seeing something about the number of cooling fins being different.

Yes, 49584 has the 93 (1 1/4") variant.

Thanks. I guess all these years I was running an M18 and thought it was a M20.

IIRR m-20's have offset connecting rods.
So if one has access to a bore A scope, it MIGHT be possible to look down the oil fill or up the drain plug to see if they are offset???:bigthink:

I sold the engine to a guy who didn't care if it was 18hp or 20hp, it was going into a Bobcat and had the right size of PTO shaft for him, so it all worked out fine in the end.