Walker MT20 GHS with Kohler CH20S Overheated....

have a 1994 Walker MT20 GHS with Kohler CH20S. The unit has 800 hours and has been used for home residential lawn mowing all it"s life. At the end of last season it started to lose power, smoke some, and apparently overheat after about 30 min of use. I pushed it to finish out the season and ran it about three times like this. She would run ok at 3/4 throttle and get me through finishing the grass or leaves (I know...probably not the best thing).

I noticed what looked like oil and gunk around one of the spark plugs. Unfortunately the way this is designed it was impossible to pull the shield and make sure it was clean. I suspected maybe a head gasket.

Yesterday I pulled the engine out of the tractor so that I could get the housing off. I found a mess. One side was completely packed with dirt and the other side was catching up. The bad side also has what looks like scorched stuff that is hard to scrape off the fins.

So.....I"m wondering what the best course of action is. I definitely overheated it. It seems to have some oil leaking by on one side. But she did still run great for the first 30 min or so until she would overheat.

Now that I have the engine out I appreciate any advice. P.S. I"m a weekend warrior with pretty good mechanical abilities. I"ve rebuilt a different engine once before (successfully). And I would never have let my engine get this dirty to overheat like this. The design of this unit is really challenging and made it impossible to get the blower housing off to clean without removing the entire motor. Really kills me because I"m the guy who lubes it and changes the oil regularly, etc.

Thinking the hard scorched stuff is leaking oil, which is what started collecting dirt, that led to the overheating.

While you have it out, it would be easy to pull the heads and look at the cylinder walls for signs of galling. If there is, may as well take it on down and see just how much damage was done.

Being it is impossible to remove the blower housing to clean things up, it is essential that the oil leaks are repaired before putting it back in service.

Thanks Steve. I think your advice is the right one. I already bought two head gasket kits. I may as well go that far and have a look inside. There isn't much choice really. Hopefully it isn't too bad.

If you open the heads up, check the valves, especially the stems to be sure they are clean.

After you put it back together, you may notice it using a lot more oil.

An overheat condition may have taken the temper out of the rings. It might be a good idea to put a set in while it is apart. If you do decide to replace the rings, be sure to find out if your Command has the hard sleeves/liners in it. If it does DO NOT hone the cylinders. You can find out more about the engine on Kohlerplus.com I think.

I had that overheating problem on my old Wards garden tractor when plowing the garden. I found this mouse nest behind the shroud. I don't keep cleaning rags out in the open anymore. I'm still running the tractor. I bought it new in 1971 and so far it isn't smoking or using a lot of oil. Hal