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2.5R21 Electric start issues

wh1630

Registered
Hello Everyone, this is my first time posting here, so here goes nothing...

Recently I came into the possession of a Kohler 2.5R21 electric plant powered by a k161 engine. When I first got the unit, I connected a lawn tractor battery to the control box's battery leads, and flipping the switch to the 'start' position, the unit spun up and attempted to start as would be expected. Since then, I have replaced the old, faulty ignition components (magneto, breaker points, condenser, and spark plug), and rebuilt the carburetor. When I reassembled the unit, I was able to get it to run using the electric start. However, flipping the start switch now causes the contactor on the left (labeled as 'CR") to make a buzzing noise as if it's trying to close. Using a wooden dowel, I pushed the contacts closed, and the unit came to life. Additionally, flipping the switch to 'stop' does not stop the engine for some reason, as I have to press the button on the side of the points box to shut it down.

The controller is a model A-233094, and I am using a 300 cca / 375 ca 12 volt battery to start it.

Any suggestions as to what could be causing this would be appreciated.
 

jack0

Registered
Age
60
It sounds like the switch is bad or wiring issues. The mag. is grounded for shutdown through the CR relay. The coil probably isn't getting 12 volts.
You might try the remote start by jumping terminals 3-4 on the wiring strip. The switch should be in the off position when doing this.
If it starts and stops you pretty much narrowed it down.
 

wh1630

Registered
It sounds like the switch is bad or wiring issues. The mag. is grounded for shutdown through the CR relay. The coil probably isn't getting 12 volts.
You might try the remote start by jumping terminals 3-4 on the wiring strip. The switch should be in the off position when doing this.
If it starts and stops you pretty much narrowed it down.
That's what I was thinking. I did use a multimeter to ensure that he coils on the contactor are receiving 12 volts. The possibility of a defective switch did, in fact, come across my mind, and I attempted to start it by jumping the terminals on the switch to no avail...
 

jack0

Registered
Age
60
That's what I was thinking. I did use a multimeter to ensure that he coils on the contactor are receiving 12 volts. The possibility of a defective switch did, in fact, come across my mind, and I attempted to start it by jumping the terminals on the switch to no avail...

Is the wiring diagram still on the cover?
So you were getting 12 volts at the CR relay coil terminals??
What leads me to believe it could be a switch problem. You could not shut down after you got it running. The switch also opens the mag. ground for the hand crank feature, but your also are getting 12 volts at the CR relay coil terminals, which would indicate a problem with the relay.
I would recheck everything and make sure all wiring connections are good.
The relay and the switch are common and available.
 

wh1630

Registered
Is the wiring diagram still on the cover?
So you were getting 12 volts at the CR relay coil terminals??
What leads me to believe it could be a switch problem. You could not shut down after you got it running. The switch also opens the mag. ground for the hand crank feature, but your also are getting 12 volts at the CR relay coil terminals, which would indicate a problem with the relay.
I would recheck everything and make sure all wiring connections are good.
The relay and the switch are common and available.
The wiring diagram is more or less still on the cover:

IMG_1326.JPG

Kinda hard to read due to the rust, but it's all there.

Earlier today I was working on the generator again, and I noticed that after flipping the start switch from on to off rapidly, the contactor appeared to work normally, but then went back to 'buzzing' when I tried again... So I'm starting to suspect it's an issue with the contactor itself.

On a side note, when I do engage the contactor (either by the switch or manually tripping it with the dowel), the generator seems to struggle to turn over the engine. For instance, after tripping the contactor, the generator will turn for a second or two and then stop due to the compression in the engine, but it will then start turning again until the compression slows it down. This would happen usually two or three times before gaining enough momentum to start the engine.

Could this be because the battery I'm using is not powerful enough? It's a 12-volt lawn tractor battery rated for 300 CCA and 375 CA.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
My first thought here was weak or inadequate battery. Stopping on compression during cranking is a sure sign. That or a bad connection somewhere. The buzzing relay is the classic sign.

I’d start with a volt meter on the battery terminals themselves, then try to crank, and see how low the voltage goes.

Keith
 

wh1630

Registered
My first thought here was weak or inadequate battery. Stopping on compression during cranking is a sure sign. That or a bad connection somewhere. The buzzing relay is the classic sign.

I’d start with a volt meter on the battery terminals themselves, then try to crank, and see how low the voltage goes.

Keith
After double-checking the battery connections in the control unit, I'm starting to think that this might just be the case. I guess I'll have to get a bigger battery then.

On a side note, for whatever reason, there now appears to be an intermittent spark on the spark plug. This is strange considering I just replaced all of the old ignition components last week, and the engine was running as of two days ago. When I removed the spark plug and turned over the engine via the electric start (which was a lot easier thanks to the spark plug being out) I noticed I'd get about two or three sparks out of it before it stopped sparking. I cleaned it off and checked its connection to the ground. Kind of frustrating considering I just installed a new magneto, new condenser, new points, and a new spark plug. Could this have anything to do with that contactor? I know there is a wire which runs from the condenser to terminal 5 on this contactor.
 

jack0

Registered
Age
60
Looks like your unit is battery start only. Terminal 5 on the relay is the kill wire terminal. The relay has to be energized to lift the mag ground. If your in doubt you could disconnect the wire and see if you can maintain spark.
Did you examine the relay? How do the wiring connections look? Do the relay contacts look good? Springs still attached. Good movement, no binding.

Maybe start by disconnecting the control wire from the starting contactor (solenoid) and concentrate on the CR relay coil. Clip on your test leads and recheck multiple times for operation and 12 volts and see how that works.

I'm sure a larger battery would help with cranking but my bet is on the relay.
 

wh1630

Registered
Looks like your unit is battery start only. Terminal 5 on the relay is the kill wire terminal. The relay has to be energized to lift the mag ground. If your in doubt you could disconnect the wire and see if you can maintain spark.
Did you examine the relay? How do the wiring connections look? Do the relay contacts look good? Springs still attached. Good movement, no binding.

Maybe start by disconnecting the control wire from the starting contactor (solenoid) and concentrate on the CR relay coil. Clip on your test leads and recheck multiple times for operation and 12 volts and see how that works.

I'm sure a larger battery would help with cranking but my bet is on the relay.

So some good news... The CR relay/contactor now works! It turns out that its ground wire was not making a solid connection with the frame of the control box. No more buzzing so far...

But for the bad news... I'm still getting a weak/intermittent spark. As mentioned before, I replaced the original shielded sparkplug that was no longer available with a recommended Champion RJ8C. The original Bendix magneto coil and condenser were replaced as well.

What confuses me the most is that I had the generator running just fine for a while, then it suddenly wouldn't start anymore...

I pulled off the flywheel again today to have a look if anything could perhaps be loose or shorting against something, and couldn't find anything...

Magneto.JPG
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
I have heard that, like so many modern things, modern condensers are frequently of poor quality. You might try testing / replacing it.

Good catch on the bad ground. A weak battery will often cause buzzing relays in starter circuits. Glad it was still something simple.

Keith
 

wh1630

Registered
I have heard that, like so many modern things, modern condensers are frequently of poor quality. You might try testing / replacing it.

Good catch on the bad ground. A weak battery will often cause buzzing relays in starter circuits. Glad it was still something simple.

Keith
Thanks! I'm glad it wasn't the relay. Turns out the ground wire coming off the relay's coil wasn't really touching any bare metal on the control box. This was easily fixed by cleaning the ring terminal and sanding off a little bit of the paint around the screw hole.

As for the condenser, do you think I should just replace it with the same one? It was just a generic one I found online, along with the replacement magneto. The funny thing is that when I remove the wire going to the top of the spark plug and hold it close to a grounded surface on the engine, I get a spark while turning it over. When I try with the spark plug, I only seem to get two or three sparks, then nothing else. I even took the old spark plug and reconnected it to the magneto and the shield to ground. Even then, I only got like three good sparks, followed by intermittent, really weak ones...

Could the fact that I'm using an undersized battery to start the engine have any effect on this?
 

wh1630

Registered
I have heard that, like so many modern things, modern condensers are frequently of poor quality. You might try testing / replacing it.

Good catch on the bad ground. A weak battery will often cause buzzing relays in starter circuits. Glad it was still something simple.

Keith

Just a little follow-up, I'm going down the list of ignition system components to troubleshoot. I replaced the sparkplug to see if the one I previously ordered was defective and still got the same results. At least I know that's not defective. As you suggested, I'm gonna take a look at the condenser. I swapped out the aftermarket condenser with the original bendix condenser and saw no improvement. I figured that the bendix condenser is worn out and the aftermarket one is just poor quality. So now I'm on the hunt for a new one... The OEM kohler condenser is part no. 220082, and I have been able to find a NOS one online, but I was worried about it being DOA just given its age. The other one I'm looking at is a STENS 055-141, which is brand new.

Any suggestions as to how I should approach this?
 
The only suggestion I can give is to observe the spark (if and when it occurs) OUTSIDE the cylinder. Is it 'fat' and blue, or spindly and white? Spindly and white almost always indicates a weak condenser.
 

wh1630

Registered
The only suggestion I can give is to observe the spark (if and when it occurs) OUTSIDE the cylinder. Is it 'fat' and blue, or spindly and white? Spindly and white almost always indicates a weak condenser.
The spark is indeed spindly and white. It seems to 'jump' in a circular motion around the electrode to the ground.

So I guess the condenser it is, then.
 

wh1630

Registered
So just a little bit of an update so far, I took a look at the breaker points and it turns out they were slightly too far apart, and after re-adjusting them to the specified 0.025", I got the thing to start up on starter fluid again! I couldn't believe I overlooked this...

I want to extend a big thanks to everybody above who helped me work through this. I'm glad all of the ignition system issues so far seem to be worked out.

Now it's a matter of replacing a few gaskets and figuring out why the thing surges during startup. It seems to rev up too fast causing the governor to close the throttle. It could be an issue with the choke though...
 

wh1630

Registered
So another update:

Still no luck with getting the engine to stay running...

I can get it to start (it has electric start) on starter fluid and with gas in the carburetor, but it runs for about two seconds before dying. When I flip the 'start' switch, the choke solenoid engages and the engine turns over and proceeds to start up. While doing so, it'll rev up and the governor arm will close the throttle, thus killing the engine. Moving the choke by hand sometimes causes the engine to try to get running again, but it still cuts out though.
I also realized that I typed 0.025" when I meant 0.020" for the breaker points.

Any ideas or suggestions as to what to do/look for would be greatly appreciated.

(Cross-posted to the Kohler engines section)
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
If it runs until the governor pulls back the throttle it makes me think plugged or misadjusted idle circuit in the carburetor, especially if choking seems to help.

Keith
 

wh1630

Registered
If it runs until the governor pulls back the throttle it makes me think plugged or misadjusted idle circuit in the carburetor, especially if choking seems to help.

Keith
Well, it turns out I had the carb set a little too lean. It starts up just fine now...
 

wh1630

Registered
I just wanted to say thanks to everyone who helped me out with this project! Since that the mechanical issues have been taken care of, I was able to focus on the cosmetic stuff like repainting. I had a local NAPA match and make a custom can of spray paint. "Petrol Blue" is an excellent match to the original metallic blue-green that Kohler used. I'm pretty satisfied with how it came out:
IMG_1424.JPG

IMG_1425.JPG

IMG_1426.JPG

With the generator pretty much good to go at this point, I'm constructing an automatic transfer switch out of a 20A contactor and a few time delay relays. I'm eventually going to mount the generator inside (with proper exhaust and fresh air venting) an outbuilding, to which it would provide emergency power.

On a side note, does anyone know if a k-series engine like this can be adapted to run on propane? It currently runs fine on gasoline, but since gasoline doesn't last long in storage, and I don't want to have a tank of gas just 'sitting around'.
 
Wow............that thing is gorgeous! Congratulations on a well done restoration of a "usable" piece of machinery. By the way, it's a manual start also.....that's what that dandy rope pulley wheel is for. I had a Lincoln "Weldnpower" with the same set up, but manual start only, and it was easy to start.....usually. Unfortunately, it went the way of all things, gone through a divorce. :(

As for the propane, I don't see why it couldn't be equipped with the necessary regulators, etc. Any Kohler distributor should have the information.
 
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