cod 121 #1 Posted December 28, 2024 (edited) Looking to change the plugs on the 418 and it appears that there are 2 gap settings. In the Kohler M-18/M-20 service manual, (the first image) it calls .035". In the 1987 Owner's manual, (the second image) it calls out .025". Any suggestions as to which on is correct? I've picked up 2 Champion Copper RV17YC plugs and I'd prefer to get it right before installing. Thanks! PS: Is it still possible to find Kohler M-18 parts, if one wanted to rebuild an engine? Edited December 28, 2024 by cod too many images Share this post Link to post Share on other sites
Pullstart 63,174 #2 Posted December 28, 2024 I would personally follow the engine manual first. 1 1 Share this post Link to post Share on other sites
953 nut 56,091 #3 Posted December 28, 2024 Kohler manual should show 0.035 for Battery ignition and 0.025 for Magneto ignition systems. This chart is for single cylinder engines but holds true for twins as well. 2 2 Share this post Link to post Share on other sites
pfrederi 17,959 #4 Posted December 28, 2024 (edited) 26 minutes ago, Pullstart said: I would personally follow the engine manual first. Service manual for Magnum Twins shows .035 as to parts ...some are available I rebuilt an M-18. Costs a lot as some parts are hard to find especially if you need over under and also at one point Kohler changed the valve angle. Tear down and reassembly is way different from Kohler singles (and used adhesives instead of gaskets)... Combined with extra machine shop cost (two of everything) $$$$ Before you plunge in I would be sure you knew what all parts you needed and make sure you can find them. I love my Kohler Twins KT17 ( I have 3) and the Mag 18 but I will never again rebuild one... Edited December 28, 2024 by pfrederi 2 1 Share this post Link to post Share on other sites
cod 121 #5 Posted December 28, 2024 5 hours ago, pfrederi said: Service manual for Magnum Twins shows .035 as to parts ...some are available I rebuilt an M-18. Costs a lot as some parts are hard to find especially if you need over under and also at one point Kohler changed the valve angle. Tear down and reassembly is way different from Kohler singles (and used adhesives instead of gaskets)... Combined with extra machine shop cost (two of everything) $$$$ Before you plunge in I would be sure you knew what all parts you needed and make sure you can find them. I love my Kohler Twins KT17 ( I have 3) and the Mag 18 but I will never again rebuild one... Thanks Paul. I think the M-18 is great but I'll keep my fingers crossed and hope that I'll be extinct before it's extinct. 1 Share this post Link to post Share on other sites
