12 hp Kohler issues

[jachady 130]

Some of you may have read my thread about a C-125 I just picked up off of CL. I'm having issues with the engine and it's frustrating me as I have two of these that I've brought back from the dead, so here's the background.

When I picked the tractor up the owner said his "mechanic" told him that the carb needed to be rebuilt, that why it wouldn't stay running. When we tried firing it, it would barely pop. When I got the tractor home, I first pulled the carb bowl. It reeked of turpentine and had a bunch of stuff floating in the "gas". I noticed the fuel line looked really rough so I bought some new line and an inline filter. I drained the tank, replaced the fuel line, added the filter and cleaned the carb. Cleaning the carb was no more than pulling it all apart and spraying carb cleaner on it. I figured I would get it running then do a complete clean. I turned over the engine until the fuel pump was spraying fuel, then connected to the carb. I then tried starting it again. Nothing.

So, then I pulled the head to check the condition of the piston and valves. There was a fair amount of crud build-up in the head around the intake valve. Evertyhing else appeared good visually so I just cleaned it up. The valves opened at the proper times and the ACR was working. No signs of head gasket leak, so I buttoned it back up.

So I decided to re-check for spark. I had checked when I replaced the fuel lines and all was good. This time, nothing. A little checking and I found the wire from the points had broken off the coil. Easy enough fix, strip the wire, reattach. Turn the key, nothing, no spark, engine doesnt' even turn over. I hadn't touched nothing but the coil wire. Nothing looked out of place, turn key on, hot wired starter - no spark but the engine turns over. I thought maybe the ignition switch so I put in a known good one, nothing. My guess here is the solenoid, I must have burned it up while trying to start the engine so much. But why no spark?

Is there a way to hot wire for spark so I can at least keep trying to get the engine to run?

Any other ideas I'm overlooking, sometimes it's better to have another pair of eyes?

John

[tommyg 154]

John, maybe I missed it somewhere in your post, but did you check the gap on the points? They could be burned allowing only a weak or intermittent spark. I would just replace the points and condenser, then while you're at it, the plug as well.

[tommyg 154]

One other thing... When you tried to crank the engine, did the solenoid "click" but the starter not turn? If so, it could just be burned contacts and a little cleaning might bring it back. I remember having a similar problem on my c125, and I know this sounds caveman like, but whenever I turned the key and the starter didn't engage, I'd whack it on the side with a wrench a couple times and it started right up! Evidently, something inside was not making a good connection and the occasional whack jarred it loose.

[Rock farmer 41]

To check for spark at the points just ground out the coil side with a screw driver.

If it sparks then the rest of the electrical system is complete and your points

Aren't getting the job done.

I find it best to completely remove the points and clean them on the bench.

And check them with a magnifying glass ( my eyes aren't so good)

I've never know a solenoid to go bad. Mostly it's corroded connections.

Remove them all and wire brush them clean.

Joe

[Save Old Iron 1,568]

Is there a way to hot wire for spark so I can at least keep trying to get the engine to run?

John,

a temporary jumper wire from the battery (+) terminal to the coil (+) terminal will supply uninterrupted power to the igntion system.

Test light on the (+) coil should be on always.

Test light on the (-) coil should flash as the points open and close. Check both the points and the condenser are connected to the (-) coil terminal.

[jachady 130]

I love this site!!!! Save Old Iron - Your hotwire idea worked and the engine started right up and purrs like a kitten. I still plan on replacing the points. But first I have to rewire, the PO had cut and reconnected a bunch of the wires. Once I have it rewired, then I'll figure out the no starter issue.

Thanks guys - John

[SousaKerry 502]

Just a thought these C-125's are shaker plate mounted engines check the little ground strap from the engine block to the frame. I usually use jumper cables to test an engine, negative to the block jumper wire from +side of coil to + on battery and touch the + jumper cable directly to the starter terminal, Not exactly safe but quick and dirty

[jachady 130]

Got it all re-wired and still no start/run with the key. I had already eliminated the seat and clutch safety switches. So I finally checked the pto safety switch, remember the engine had turned over when I first started all this. I jumped the wire harness and it fired right up with the key. So, foregoing everything OSHA has taught us, I eliminated the last safety switch. Now it starts, runs and shuts off with the key. It's a beautiful thing. Hooked the tiller up the rest of the way and headed to the garden, this is the tightest tractor I've ever driven. I love it.

thanks again guys - John

[Martin 2,133]

john, just found this thread, great you found the problem.

i gotta say with the c125 i had exactly the same problem with mine when firing the engine for the first time while rebuilding the tractor. i jumped the pto switch right in the electrical plug. all the other switches had already been bypassed by the previous owner. i guess its just like my sixties tractors now.

[SousaKerry 502]

I can't tell you how many times I cant get my c-175 to start and just about start to get out the jumpers and then finally remember to check the PTO switch.

Think i need to wire in a light on the normally open contacts, light on = no start

[jachady 130]

Yeah, I already have it jumped on the silver tractor as well.

I'm putting the new one to the test this weekend, it goes up north to try tilling in the woods. We'll see if it does as good as it's Silver brother.

John