Kohler M18 skip

[jaynjeep]

I have faith!! I think you got it nailed down... can't wait to find out!

[DieselDoctor]

Slowly going back together. Heads and manifolds on, starter bolted up.
Project will be on hold for a couple days. I need to replace a sliding glass door to the patio. Roller seized on the slider and wife decided she wants a vinyl clad door. Rollers - $40, Complete new door - $600 which one do you think she'd choose?

[jaynjeep]

Originally Posted by DieselDoctor

Slowly going back together. Heads and manifolds on, starter bolted up.
Project will be on hold for a couple days. I need to replace a sliding glass door to the patio. Roller seized on the slider and wife decided she wants a vinyl clad door. Rollers - $40, Complete new door - $600 which one do you think she'd choose?

Those Mag/KT engines are slow going back together.. not the easiest thing in the world to work on!

I guarantee my wife would choose the new door!

If Mama aint happy aint nobody happy!! So you better stop the cub progress and get the door!!

[DieselDoctor]

It still skips! After finishing up assembly of the M18, I set up my run-in bench and started it up. The carb was real close as far as adjustments but immediately I noticed the same old skip. Knowing what I did to the internals, and a complete change-out of the fuel system from my M20, I decided to look at ignition AGAIN. After removing the fan shroud and looking over the new coil once more, I moved to checking the flywheel. It's the only part on this POS Magnum I haven't touched. Using a piece of iron I checked both magnets strength - they seemed equal and strong. Then I looked at the special bolts holding the magnets onto the flywheel, thinking maybe they weren't tight. Attached is a picture showing that the heads of the two bolts. They are all chewed up from vise-grips. SOMEBODY HAS BEEN IN HERE. I missed that during the first tear down and inspection. Not having a flywheel out of a running M18/20 to compare to, I purchased a used flywheel off a running engine from a vendor and will try that. The used flywheel is due here in the middle of next week. Time will tell. The magnet/holder is not available as a separate part, so swapping flywheels seemed to be the only choice at this point. I'm not giving up just yet.

[ol'George]

Originally Posted by DieselDoctor

It still skips! After finishing up assembly of the M18, I set up my run-in bench and started it up. The carb was real close as far as adjustments but immediately I noticed the same old skip. Knowing what I did to the internals, and a complete change-out of the fuel system from my M20, I decided to look at ignition AGAIN. After removing the fan shroud and looking over the new coil once more, I moved to checking the flywheel. It's the only part on this POS Magnum I haven't touched. Using a piece of iron I checked both magnets strength - they seemed equal and strong. Then I looked at the special bolts holding the magnets onto the flywheel, thinking maybe they weren't tight. Attached is a picture showing that the heads of the two bolts. They are all chewed up from vise-grips. SOMEBODY HAS BEEN IN HERE. I missed that during the first tear down and inspection. Not having a flywheel out of a running M18/20 to compare to, I purchased a used flywheel off a running engine from a vendor and will try that. The used flywheel is due here in the middle of next week. Time will tell. The magnet/holder is not available as a separate part, so swapping flywheels seemed to be the only choice at this point. I'm not giving up just yet.

Now your getting somewhere, I didn't think you problems were valves, they just were not that bad and your statement of it sounding like a SBC running retarded is the key.
Why in the hell did somebody attempt a change of the magnet trigger?? they just don't give problems.
Post some different angle pix of that thing.
-----Now on the new/used one in transit, CAREFULLY check the magnets on the inside,--- for the charging system.
They are known to come loose after this many years.
That said, no problem if they are, as they can carefully be re-glued with epoxy, paying attention to spacing and polarity.
BTDT,--- I changed a complete set broken/missing magnets using a donor set from a junk series one.
As you know, they do not affect the ignition system, just the charging system.

[DieselDoctor]

George -here's a few more pictures of the magnet assembly. Since I don't know the history or integrity of this flywheel assembly, I decided to pull the magnet off the flywheel to see how it is located. It's scrap iron now except for salvaging the ring gear. As the pictures show, the bolt holes in the magnet holder are tapered but the underside of the bolts are not. This allows the magnet to be moved around under the bolts by about fifty thousandths side to side. I don't know how many degrees of timing that would be, but I would guess at least a couple anyway. Your thoughts?

[Alvy]

Stan were those countersunk bolts that hold the trigger on loose or just mucked up by the vice grips and still tight? If they weren’t loose I don’t see how that could be the issue but as always I could be wrong. Them being countersunk centers the trigger exactly where it needs to be.

[ol'George]

What I'm wondering, is what the magnet assy came out of?
Obviously if the bolts are not flat heads, it will not locate correctly.
But it would be my thinking it is only going to be a degree or two off at most.
I'm wondering if the magnet is the correct trigger for that coil location.
course' there is the other question, is the flywheel correct?
is the keyway cut such as the magnet is in the correct location for the coil location, allowing the timing to be correct.
also is there a N/S polarity issue as it is passing the trigger in the coil?
another thing comes to mind,IIRR, there is an arrow on the aluminum coil mounting bracket,
that attaches to the head, I believe pointing to the flywheel??
Definitely do some comparative detective work when the replacement flywheel arrives, that should turn on a few light bulbs, I would think
My guess the firing of the coil is not occurring @ the right time causing the whole problem
But we are just brainstorming here, this is something out of the ordinary to be sure.

[ol'George]

Well I just did a search on ebay for M-18 flywheel, there are several and they look to me, like yours,so I am still scratching my head.
Is the mentioned aluminum coil bracket mounted on the head, correctly positioned?

[darkminion_17]

Maybe the ignition switch is bad...