To answer your question about camshaft part number change...YES. The tech manual talks about the changes in the inspection and reassembly section.

[QUOTE=DeltaCub;441831]To answer your question about camshaft part number change...YES. The tech manual talks about the changes in the inspection and reassembly section.[/QUOTE

Yes they changed cam/lifters/exhaust valves during the m-18 model run, IIRR the later ones ran 30* exhaust valves vs the earlier *45/45 I/Ex.
It is covered in the manual.
But timing marks remain the same.
They do have different valve clearances but not much.
Read about it in the service manual, as Beth mentions :beerchug:

I am being good so Santy gives me a present this year.



https://drive.google.com/open?id=13v...wjcOvnE1uWtSqJ

https://drive.google.com/open?id=1LI...id5CX0sK64Xj16

https://drive.google.com/open?id=1fu...jec9nzIs1EpRNK

Thanks for posting the bulletins Lew! Now I need to go thru and identify what is in the engine. I'm almost positive the cam does NOT have the orange paint. Trouble is I can't see it from my easy chair and it's cocktail time!

Lots of good info here. Lew, Beth, the old man.... what's his name again? :bigthink: (Just jabb'n ya George!)



Stan, you already figured out the valve springs are the same. The difference in the valves is the angle, as already mentioned.

Remember, this is a flat tappet motor. I doubt the valves are floating. The flat tappets leave odd marks on the cam, but it's normal. I wouldn't worry about it.

Timing marks are intact, and correct. I am not going to look up all the info, but the only cam difference that I am aware of is related to generator sets. Most of the Kohler engines set up for gen's had a different cam and governor assembly. (At least the K series did, and I assume the twins did too. It just makes sense as they are designed to run a CONSTANT RPM, and it can't vary, or the electrical output is changed.) I doubt since everything inside looks good, that it has been changed. At least now, you can rule it out. I'm sorry you had to split the case to find out.


I would be checking the piston rings. Take one off and put it in the jug and measure ring end gap. Maybe someone did a ring job and put it together without setting the gap and they are too tight. If that is the case, I would have thought compression would be higher though..... I too am grasping at straws.

YES, the stator CAN leak A/C voltage, and it would mess with a magneto. I've seen it before on other engines. (Just not specifically a Mag 18.) It is my experience that when that happens, you cannot measure it. It doesn't take many A/C volts (or amps either one) to mess with the Magneto. Unfortunately, you can only remove the stator and run it without to see if it helps. If it was a simple alternator, you could just remove the belt..... but, it is what it is. That is a good thought. Since you have found nothing else, it's something to look at.

While you have this thing apart, I would pull the oil sump and clean it. I would also suggest pinning the cam gear. I'm not big on doing that mod unless it's necessary, but you are right there, and it would be easy to do. Personally, I don't like unbolting rod caps and putting them back on, but maybe you already took them off. I only was going to suggest leaving them bolted to the crank and do a "hand check" to make sure they aren't too tight or loose.

Keep going...... issue is there somewhere. Just to state facts, I've done things like this before, put it all back together and it ran perfectly, never knowing what the issue was. Frustrating, but some days I'll take luck over being good. :biggrin2: Maybe you'll get lucky!

Thanks Jon. The plan now is to go thru and check everything as I would during a bare block overhaul. The rods are still on the crank and feel good so I'll leave them. I don't like to pull rods apart either if they're ok. It will get new rings. The bore shows virtually no wear, but I will measure of course. Pistons have no wear to speak of, just some minor rub marks on the skirts as is normal. As this goes back together, I'll run it without the stator just to make sure. First of the week I'll start washing parts and put together a parts order. I didn't plan to rebuild the M18 when I bought the 782, but it is in nice shape and is probably a keeper. Stay tuned!!

:popcorn::popcorn::popcorn::popcorn:

Not much new here. I started on re-assembly today, cleaning the block halves, inspecting the oil pump, then installing the cam and crank then bolting the halves together. I miked the cylinder bores and they are worn exactly .001 from standard dimension. The rings are smaller than I am used to working with, but they seemed like they had very little tension as I removed them from the pistons. Compression was at 90 - 95 psi in both jugs, so it is down a little. It will be getting new rings and gaskets. The pistons look like new. No scuff marks on the skirt, and just a little carbon above the top ring land. So far nothing mechanical that was causing a skip. Tomorrow I'm going to pull the valves and see what angles have been ground compared to the cam information Lew provided.

Get those valve seals for about $1.00 each not the crazy prices of $20 +
I guarantee the old ones are as hard as a groom's wedding night.:biggrin2:

I bought aftermarket pistons fairly cheap. Paid about $50 to get the valves/seats ground. Should have went ahead and had the jugs bored as .010 pistons were about the same price as std. Like yours, everything miked in spec. I used aftermarket gasket kit as well, so far so good.