'64 Toro 12 w/Kohler K301A

Hey guys, I'm new here, looking for some input and maybe a good source for replacement parts for a 52 year old tractor engine.

This Toro was my dad's since around 1967, he never changed oil, spark plug, any onboard ignition or fuel system parts. He just drove the thing, using it to mow, snow blow, pull a 4' X 7' trailer to haul firewood out of deep woods, and to drive to the neighbors down the road. In other words, the old man did his best to drive that Toro into the ground. When he gave it to me it ran dependably, if not rough. I gave it it's first oil change in 50 years, a new Champion spark plug, kitted the carb (had to use the old needle as the replacement was NOT the same as original), did some tinkering with mixture settings, and had that Kohler running like a top...For a year.

I had her in the shed for the first half of this summer until I needed to haul that 4' X 7' trailer full of brush (I inherited the trailer as well) yesterday. The old girl popped to life before the first crank was done and she ran perfectly for about 10 minutes. I had purged the fuel tank and replaced old gas with "non-ox", the Minnesota version of alchohol free fuel. All my single cylinder engine gear loves the stuff.

Anyway, I stopped the tractor and let it idle at low speed while I loaded the trailer (the battery seemed weak, the generator/starter keeps the charge up), and all of a sudden the Kohler started to bark and backfire, then suddenly quit. I can get it to fire, but won't start and run. Took the carb tank off and checked the needle/seat, was clear. Checked for spark (ouch, got spark!). Put a couple ounces of Seafoam in the tank and checked my mix settings on the carb and still: Bang, but no run.

Does this sound like a familiar trouble shooting issue? I'm no small engine guy, I know some of the care and feeding, but as far as diagnostics go I'm at best a novice...

I appreciate any help.

---Eric

Might need to pull the head and check for a stuck valve. The stems will get carboned up and stick due to the oil not being changed regularly.

Had one or two that did that and the cure was to replace/gap the points and time it. They still made spark it's just the ignition was so mucked up it wasn't spark at the right time

Probably time for new points and condenser
time it like BOB says.

Thanks guys, points and condenser wasn't a thought, being as I'd had the old dog running so well. But yeah, it's probably been 52 years...Mark, pulling the head seems invasive for a know-nothing like me, if the ignition parts don't solve it, I'll have you come up to the northwest of MN to give me a hand with it, eh?

OK, vintage engine oem parts...Kohler still have 'em?

i have had problems with new champion spark plugs. try your old plug.

Before you pull the head, check to see if there is compression with a gage/tester. It sounds like an ignition issue to me. After you get the points close (the gap determines the timing) put a timing light on it to get it "right". If it is a Kohler, there is a downloadable manual on the Internet. A lot of times the point gap as determined by using feeler gages does not get the timing "perfect".

None of my engines large or small including a couple of "K" series Kohlers have ever complained about the E10 I use in them. Maybe I'm just too
dumb to know any better. Could someone enlighten me?

The points contacts look brand new, gap is
.020. I was surprised. Condenser looks like
a 52 year old condenser should, greasy and
dirty, but I am getting a powerful arc
through the points and the plug electrode.
The oem webstore I found displays what looks
like 100s of variatons on the K301. I did
find my spec (page 7 of 33), and they claim
parts are in stock.

...but I think I'll go ahead and tear into
that carb one more time before I order
anything.

K series engines have ACR (Automatic Compression Release) compression tests are a bit difficult