I have a 1991 Scag STZ52-20KH, serial number 1582 zero turn, and I would like to repair/rebuild the engine. It is a Kohler M20S. I tried the black light trick for reading the spec number on the remnants of the label. I was unable to make out any numbers. Scag customer service said the spec of the engine for my serial number is PS-57515. This number doesn't match up with any of the Kohler spec charts that I could find. I would appreciate any help. I need the spec number to order the correct parts.
Identify Kohler Engine Spec where label is peeled off
- Thread starter bluheron
- Start date
sethpayment79
New member
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- Nov 15, 2025
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Did you figure this out? If you have a model number on the Scag you can go into their parts lookup and it will show the engine used on it and spec for a Kohler engine...
Hey @bluheron, with older Kohlers like the M20S, it can get tricky when the label’s gone. If Scag told you PS-57515, that’s probably their internal reference, not Kohler’s spec number. The easiest way is to use Scag’s parts lookup with your mower’s model and serial number. They usually list the exact Kohler engine spec there so you can order the right parts without guessing.
