K161 running unreliably.. just old, or bad coil?
 

I have to admit for starters, this old Kohler isn't on an IH machine, it's on a Troy Bilt tiller, but this is a fairly busy Kohler forum, and I'm already signed up here, and I think the info still applies, so I hope it's alright..

I picked up a cheap K161, 7hp, that was supposed to run, but leaked gas. I just bought it to rebuild it and put it on a tiller, but it had good compression so I decided to see if I could get it running. I fixed the gas leaks, cleaned everything, and eventually got it running, and it ran alright on the ground, so I put it on the tiller, and I've had lots of problems since. It'll often pop, trying to start, then sometimes it'll diesel backwards for a few shots. Or it'll try to run, pop miss miss miss pop, and keep going at that for a minute but never catch on. Then, occasionally, it will get all the way up to the point of running, and it can run for a long time, 10-15 minutes, and till a little. But giving it throttle often upsets the balance and it falls flat on its face. I'm still planning to rebuild it, so I figured I'd just start buying the parts now, and see if they made a difference. New carburetor, new condenser, new plug, not much change in the run, if any. Mystery oil, no change. It's frustrating because it's intact, it'll go, but it's not good enough to be practical. I'm used to rebuilding these engines when they're all worn out and the rod goes. Run quality issues are typically a matter of adjustment. But, maybe this 45 year old engine is just gracefully hanging on right into the end of its life?

The last external part I could replace before rebuilding is the ignition coil. It's a pull start engine, so it's the type that rides against the flywheel, not the external can. Could a coil malfunction in a way where it has major issues providing sufficient spark power, but then still gets the engine up and running pretty smoothly now and then?

Or do these symptoms sound more like an engine that's just worn out, but hasn't failed catastrophically yet?

Thanks

Points filed and adjusted..

Personally, I don't buy that notion.

I would start with the Fuel Delivery (Carb). Then it would be electrical (points and/or condenser).

If it's a rope start with internal coil, sounds like the old coil is bad.
They are hard to find, I finally used an old coil from a 4 hp Kohler I had.
It needed a little help getting it to fit, IIRR I made a shim for the bar the coil slides on.
it then run nicely but it is not being used now, it is out of an "original" cub.
Rope start "original" engines are not common.
Wished it had the recoil, but sadly I just used a rope.
After 60 years, those coils do go bad, usually it is the insulation/cracking that allows shorting.
Good thing is your pull arm does get a good workout and no gym time is needed :biggrin2:

What is the Spec Number on your K161?

No spec numbers on the K161, label was removed from shroud at some point. A google search of k161T will give you at least a visual representation of what I have, so it may be a k161T. Recoil start, internal coil, top fuel tank, muffler out the rear in line with crank.

As I said originally, I've replaced the carburetor, condenser, and spark plug with new parts. Carburetor will not tune in any better to improve the run of the engine.

I would look at the Magneto Coil and/or Timing.

There are a couple of different magneto setups that these things use.
A picture of what's under your flywheel would go a long way in determining what you have so that we could provide some useful suggestions.

If it helps the spec number on the K161T on my Troybilt is 281271J. It’s a 1977 motor. Coil for that one is 4775520S. Over $150.00

Off shore crap, but if your shotgunning, why not?
https://www.ebay.com/itm/33379683708...Cclp%3A2047675