Kohler courage 20 toro LX425

[mustang492]

ok first I apologize for this being long but I feel as though the background info may help. as the title says I have a Toro lx425 with a Kohler courage 20. Last year, in an effort to figure out why the mower would run for ten minutes then misfire I replaced a multitude of things. Carburetor, ignition coil, spark plug, fuel lines and filter, even adjusted the valve clearance(it was slightly off from the book but within tolerance). All that and it ended up being carbon on the valves and two boltless of sea foam worked wonders. well I noticed an oil leak this year and assumed that it was the usual valve cover gasket issue that these mowers are known for so the other day I was working it pretty good hauling dirt around the yard in a gorilla cart keeping an eye that I didn't run light on oil. I pulled the cover and the heat shield only to find out that the valve cover was not leaking it was actually coming from under the flywheel(the upper shaft bearing).the engine and frame were covered in oil as the flywheel was flinging it everywhere throughout the day. I shut it off to clean it off again, go to start it and the starter gear comes up, shaft spins, but does not turn the flywheel. I tried at least five times to start it and same thing each time. after taking the starter apart I noticed everything inside was covered in oil so probably no friction. Flash forward to today and I get my Chinese knock off ( I know) from amazon and throw it on and it cranks way faster than the original one. the mower almost starts and puffs a bunch of smoke and pigs out. I figure maybe I don't need the choke cause this thing cranks so fast so I kill the choke and same thing happens. wont fire up and the exhaust smells horrible. I let it sit thinking it was flooded and still would crank over like a champ but not run. It also backfired twice. Never actually ran though. this thing was running two days ago. Its not the carb fuel line or filter or even the plug. can the ignition coil go bad from me cranking the old starter and the flywheel not turning with the starter gear spinning like that? I'm not even sure if the two are connected. if need be i can try to attach a video. thanks

 

[Ronni]

The key is all the oil being flung out by the flywheel. This engine is known as "the bucket engine" because the crankcase is sealed by a flat top that is bolted to the engine below the flywheel. What has happened is, the lower crankcase has developed a crack in the right side next to the cylinder head because the bolts securing the top cover have become loose because of vibration and oil is coming out of the gasket seal below the top cover. This is the kiss of death for the engine because there is no good or lasting repair for this crack. I had the same thing happen to my Cub Cadet LT1045 with the same Kohler engine after about 10 years of service. I was able to buy a short block on Amazon for $742.04 with free shipping. (https://www.amazon.com/gp/product/B00CNX3ZCW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) Everywhere else it was over $1000. I used all the outside parts of the old engine to install the short block into my mower and it works great again. I also learned that I had caused the failure by running the original engine at too high an RPM and also by cutting high grass too close to the ground; you should only cut the top 1/3 grass height at a time to keep from stressing the mower. You should also only use sharp blades for easy cutting. In other words, I was overstressing the engine needlessly.