Problems with Kohler Command 20

DrewRiley

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I posted this in the small engine forum as well, before I realized there was a Kohler sub-forum. Mods, feel free to merge if necessary:

Hello all,
Hopefully the following doesn't drone on for too long, but I want to be thorough with details:

Recently I was given an older Zipper-TS zero turn with a Kohler Command 20 in it. The original owner stated it had electrical problems that he couldn't figure out, which ultimately turned out to be just combo of a stuck fuel solenoid, a couple of bad ignition coils, and I had to bypass one of the safety switches from the engine. Once that was taken care of, the engine fired up and ran great, until I saw oil blowing out all over the motor.
From what I could see on a few different seals and gaskets that were easily accessible, many of them seemed to be cracked or dried out, so I bought a full seal kit and replaced nearly every seal and o-ring on the entire engine. Ultimately, everything went back together, and everything seemed to start up and run fine with no more oil leaks. I mowed my entire 2 acre lot with no trouble, and parked the mower for the week. I might add that this motor does seem to run quite hot, and does not have the optional oil cooler, but that seems to be standard with this Command engines from what I've read.

The next time I tried to start the mower, it had some trouble starting, and seemed to be losing compression after the first couple attempts to get the engine to start. It seems like it would try to start firing, but then there would all of a sudden be zero compression. If I waited a couple of minutes, I would get compression again, and get a couple of chances to restart. Finally on about the 4th or 5th try, I got the motor to start and pulled the mower around the side of the house to the front of my garage. It was then that I noticed the oil filter's o-ring had blown out, and oil had been pouring out everywhere for the 30 to 40 feet I had driven the mower.

I put a new filter on, topped off the oil, and then tried starting again, but now the engine kept dying immediately.

I tried reading up on compression loss, and ended up taking everything back apart to look things over, but nothing really looks off (which isn't to say I might not have missed something). I did go ahead and take the lifters out and bled them this time, wondering if maybe that was contributing. After putting everything back together, the engine immediately started up, ran for about 3 seconds (it did seem like the rpms were really high), and then it died. I started hearing backfiring/popping when trying to start it again, so I took the air filter off and see that the carb is now spraying fuel out of the top. I checked the float and needle and they seem fine, but I'm kind of at a loss for what to check next, or why I started with an oil leak and now have a fuel leak/carb issue. I also did briefly notice that I was still losing compression as before.

Anybody have any earthly idea what's might be going on here, or what I can check? Seems I only know enough to get myself in trouble. ;) Any insight or suggestions are appreciated.
 

DrewRiley

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Well, I went ahead and ordered a rebuild kit for the carb just for the heck of it. Couldn't hurt anything anyway.
I also ordered a compression tester and a leak down tester, at the very least for a sanity check. Who knows... maybe lead me somewhere.

In the mean time, I welcome any other suggestions for things I might look for / look at.
 

bertsmobile1

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If you are getting that sort of crankcase pressure then you have a compression leak into the crankcase.
Can be broken piston rings, blown head gasket or just a stuck breather or a combination of all 3
Lesser crank case pressurization causes cracked head or loose valve guide.
The loose valve guide will cause random no compression issues.
At this point in time, forget the carb kit and pull off the head / heads as Kohlers come in both single & V twins at 20Hp
Kohler have their repair manuals available on line to USA web addresses or you can go to http://www.mymowerparts.com/about_us.php
Then hit Free Manuals in the red navigation bar and work your way down to the Kohler section.
While you are there do the same for your Cub as from memory the engine section of the Cub manual is better than the Kohler manual
 

DrewRiley

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Well, just to give a quick update, I think I figured out what was wrong. Turns out that I had partially stripped one of the rocker arm mounting bolts. (OOOOPS)
I bought a helicoil kit, repaired the stripped threads, and tightened everything back up, and the mower fired right up.

I think some of the issues I had been seeing had to due with the mounting bolt loosening up, before it finally gave out.

Hopefully that's that!
 
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