Sunstar PTO Clutch

[rlschoemer]

In process of replacing the Kohler M18S in my Sunstar with a M20S. Well the M20S has the 1-7/16 inch shaft. Don't feel like swapping crankshafts, so started looking for 1-7/16 PTO clutches. Found Ogura clutches on-line but not able to find any Warner listings. Does anyone know if Warner makes a 1-7/16 PTO clutch? It is easier for me to obtain Warner items. Any help appreciated.

[Ronald Hribar]

I have Magnum 20 in my 7117 , for some reason or other, I do not think that is the correct size, will be in garage later on to measure . will let you know. I got my clutch from SLI

[ambler]

I believe standard M20 shaft is 1 1/8"

[Ronald Hribar]

Yes that is what I measured on mine 1 1/8

[Al]

Hi, There is more to the clutch issue than shaft size. The pulley diameter and the groove width are an issue also. Next is the torque rating and finally the crankshaft shoulder. I haven't looked and counted, but I think there about 20 or 25 crankshaft part numbers that used in these engines. The spec # of the engine defines what crank, charging system, air cleaneer, carb, starter, engine controls, ducting, controls, flywheel, flywheel screens, flywheel drives and more. Back to the crankshafts. diameter, key size and pto length are factors. Next the shoulder the clutch butts up to and how far forward it is located from the closure plate on the engine. Some are almost 90 degrees with a very small radius, some have a large radius, The base of the rotor in the clutch usually has a special washer or spacer that has to seat properly on the shoulder on the crank. This controls the spacing of the rotor from the coil. If the spacer is too thick, the rotor is pushed too far out of the coil the clutch won't energize reliably, too close and the coil gets destroyed. John Deere 318 and 420s use a l 7/16" inch crank, but this clutch won't work on the CH engines without some reworking and special made parts. One of the little things we do when making these clutch parts is to put "Play Dough" between the rotor and the coil. We then measure the clearance and then revise the spacers to make the clutch properly. Another issue is how much current the coil draws, this determines the strenght of the magnetic field that pulls the clutch plate in and how much torque,(how much engine power) the clutch can handle. This is a far greater project than just finding "A" clutch with a 1/7/16" shaft, hope all comes out OK for you. Al Eden

[rlschoemer]

Thanks Al - That is the info I am looking for. I have access to a complete machine shop so adapting the clutch should not be a problem. I am also working with an OPE shop that has been in business 40+ years, most as Simplicity dealer. We are just looking for a Warner 1-7/16 clutch with a (2) groove pulley. From their we hope to be able to adapt.