Kohler M18 skip

[DieselDoctor]

Ya know George I read your post twice letting everything sink in, and finally the brain cells lined up. No, I haven't checked the coil mounting bracket! But I will first thing tomorrow. All I was told about this 782 tractor was that the original engine blew, and the owner found an 1811 and parted it out stealing the engine, driveshaft and rear to put under the 782. Yes, he removed the cast iron rear and installed the aluminum one. Idiot! I have no idea what pieces and parts may or may not have been changed. My 2072 is my snow plow, so I can't down it and pull the flywheel/coil to try it until spring. Hopefully the flywheel I've purchased makes a difference.

[DieselDoctor]

Alvy - the bolts were tight, and had red Loctite on them. The taper on the magnet mount is much larger than the shoulder under the head of the bolt allowing some movement.

Lew - I've run the engine without an ignition switch, does it still matter?

[darkminion_17]

So if it still skips when you unplug the switch when it is running ,that rules out that.
So your saying the magnet on the flywheel moves even when the screws are tight?

[DieselDoctor]

The screws will tighten against the aluminum but there is no matching taper on the underside of the head of the bolt to lock into the corresponding taper in the magnet mount. There is a slight shoulder but smaller in diameter. With the screws loose, there is some side to side movement. Once the screw is tight, no movement. You can tighten with the lash taken up in any position within the range of movement, about .050" Not very much, but probably a degree of timing.

[ol'George]

Originally Posted by DieselDoctor

The screws will tighten against the aluminum but there is no matching taper on the underside of the head of the bolt to lock into the corresponding taper in the magnet mount. There is a slight shoulder but smaller in diameter. With the screws loose, there is some side to side movement. Once the screw is tight, no movement. You can tighten with the lash taken up in any position within the range of movement, about .050" Not very much, but probably a degree of timing.

Doc,
I thought of this erratic heartbeat patient many times last night while trying to sleep.
I don't know if we are chasing our tails on a cold and worn trail on this one.
You have seen evidence of other "golden screwdrivers" on this thing all along.
The valves were previously investigated and the latest flywheel evidence.
Wondering just how long this has been going on with previous owner/(s) ?

When the replacement flywheel arrives, if the condition still presents itself can you post a video with sound?
Myself, and I'm sure jon, would like to view it as others.
Honestly, I'm not optimistic.
But i'm the kind of guy that don't give up CPR till the patient is cold and stiff

[J-Mech]

I'm lost....
Stan, just go bolt the magnet back on. Why would the flywheel be junk?

That magnet being loose wouldn't cause a skip.
I'd really like to hear this thing run....

[DieselDoctor]

Agreed. Not going to give up either. There is one component that isn't right somewhere. Just have to find it. After tear down and refreshing the innards, I'm sure cam and valves aren't the problem. Given the skip and the exhaust note when running sounds like timing, so it's got to be coil (changed) coil bracket, or flywheel to change the spark timing. I've taken the entire fuel system off of the 2072 including manifold and saw no change so it's not fuel. The next time I run the engine, I will try to take a video again. Last time I used my cell phone and the sound was terribly distorted. I'll see if someone can loan my a better device like a GoPro or similar.
I appreciate everyone's help and comments. Working on a puzzle like this one, you begin to second guess yourself. Having friends like you guys makes this bearable and I value your past experience. Thank you all!

[DieselDoctor]

Sorry Jon, I didn't see your most recent post until I had sent mine. I can bolt the magnet back on, and probably will if I can prove that the magnet holder is correct for this flywheel. When I made that statement, I was a little aggravated with myself that I had missed the chewed up bolt heads. I meant that the flywheel was "junk" not knowing if it was correct so no harm in taking the magnet off and possibly losing a fixed point for timing.
As mentioned I'll try to record something when I run it again.

[jaynjeep]

I admire your persistence! I am with George on this one.. there is no telling how long somebody else hunted this same issue.. I believe you inherited somebody else's problems.. I also agree that you have narrowed it down to the ignition or a timing issue..
I've been down similar roads many times before.. it's very frustrating but in the end when you do find the issue it is also very satisfying!

I'm willing to bet that someone else caused this issue many years ago with some little small thing that all of us are missing

Stick with it.. you will find it!

[DieselDoctor]

George - I checked the coil mounting bracket and it is installed correctly with the arrow pointing towards the top of the crankcase.
When I ran the engine this last time after doing the valves and rings. I installed new plugs, this time using AC's. There was no change in the skip but I wanted to read the plug color. Mixture was pretty close as I had mentioned. After running the engine for about 5 minutes on and off, I shut it down, frustrated. I just pulled the plugs and cyl #2 which is left bank facing the flywheel is noticeably darker than #1. This is the plug furthest from the coil too. Now seeing as the motor isn't smoking from a rich condition, is the dark from the misfire or is the #1 plug more white from lean? I know I have said the other fuel system from the 2072 made no difference so what is causing the difference in plug color from side to side?
Anybody got a known to be good coil they're willing to loan for a test? I don't really want to shell out $100 for another coil until we pinpoint the problem.