Kohler M18/M20 questions
 

I have recently acquired a couple of these (finally found some horizontal versions that were quite reasonable)
1 runs good as is, (after a carb swap) one runs but smokes and #3 (the 20 hp) sat outside and the cylinders rusted up. I got it freed up but looking at the tops of the Pistons I can see about half of the top ring so I am suspecting that the jugs on that one will need bored almost for certain. Looking around I don't see much available in oversized Pistons and rings,
Are oversized parts available for them? Even if they're offshore aftermarket parts I guess.
I know that they are a discontinued series of engine from Kohler.

On another note I think that the smoker is a crankcase breather issue.most worried about O/S parts for the 20.

This best I can offer your general question, is a general answering. That being YES.

cool. that helps. looking around the usual parts sources I don't see as much for them as for the K singles.

You aren't going to find many aftermarket parts available. What you find will be standard. There are some oversize pistons out there, but all I've ever found was .010" over, and they were in the $60 a piece range. If you need undersize rods, I'm not sure if they make them anymore. If you do rebuild it, get your wallet ready, they aren't cheap. The KT's and Mag's twins just weren't meant to be rebuilt. They were a throw away motor from the beginning. Main bearings are just "inserts" not actual bearings like the K series and the later CH motors.

When I rebuilt my M18 and also my M20 I was able to find decent used jugs and pistons on Ebay for a reasonable price. The used parts were std. bore within wear limits, and I bought new std. pistons. Jugs from a vertical are different but can be modified for use in a horizontal application. A hole needs to be drilled in the valve box as a drain.

Ah,no,----- Vertical jugs need nothing done to them to use in a horizontal
position, but horizontal jugs used in a vertical position need a drain back hole in the valve box to correspond to the drain hole in the block.
As far as undersized rods, they are available from Batforkids on ebay as well as
oversize pistons, last time I looked.

I didn't think he had undersize rods for the KT/Mags...? :bigthink:
But I didn't go check......

152987229129 ebay .010 under, kohler
Bakt4kids .010 141066871950 aftermarket, he also sells in a "kit":beerchug:

Ill have to check that out. thanks.