K321 Points shooting out sparks

[wyldewon]

I'm working on a 1979 1450 with the K321 engine.

The engine seems to run fine most of the time but occasionally, It sounds like it's under a load. The engine sounds changes and the governor arm opens the throttle and the engine stumbles, then recovers. I removed the points cover and was adjusting the ignition timing when I noticed each time the engine stumbles, the spark at the points gets very bright and sparks shoot out from the points contacts.

The points are fairly new Kohler OEM and I checked the coil and condensor with a multimeter and they test ok. I removed the wire from the coil to the points and checked it for chaffing or short but it was ok. Replaced the coil wire, tried a different condensor and a different spark plug but no change. I also used a points file to clean up the contacts.

I also removed the push rod for the points and saw that one end was slighty rounded at the tip. The tip on the other end looked perfect.

To rule out anything with the hydraulics, I removed the drive shaft and no change. It does have the original PTO attached to the front of the crank but it is electically disconnected and the belt removed.

When its running good, the spark across the points contacts is very small.

If you have any idea what would cause this, I'm all ears!

[Billy-O]

Since you checked everything that immediately comes across my mind..... I would check if you have good ground.

[ironman]

First off, it is normal to see some sparking across the points.
Second off, the condenser is basically a capacitor wired across the positive and negative side of the points.
In this case the condenser's (i.e. capacitor) job is to maintain a constant voltage across the points which reduces voltage spikes, thus minimizes sparking, resulting in less burning of points contacts and extending it's life.
Granted, it could be bad and cause what you are seeing.
Thirdly, I've personally never heard of observation of the points spark brightness being used as an engine diagnostic procedure, but live and learn.

All that being said, since you are happy with everything that you inspected and tested ignition wise, I'd go back and look at a governor/carb/fuel starvation possibility.
Just my

[wyldewon]

Thanks, I'll be checking the grounds this morning.

[wyldewon]

Originally Posted by ironman

First off, it is normal to see some sparking across the points.
Second off, the condenser is basically a capacitor wired across the positive and negative side of the points.
In this case the condenser's (i.e. capacitor) job is to maintain a constant voltage across the points which reduces voltage spikes, thus minimizes sparking, resulting in less burning of points contacts and extending it's life.
Granted, it could be bad and cause what you are seeing.
Thirdly, I've personally never heard of observation of the points spark brightness being used as an engine diagnostic procedure, but live and learn.

All that being said, since you are happy with everything that you inspected and tested ignition wise, I'd go back and look at a governor/carb/fuel starvation possibility.
Just my

Thanks for the reply. As to the three points you made...
1. Agreed
2. Agreed
3. Agreed, I never use the points spark brightness as a diagnostic tool either, it just happens to be what I observed. I was scratching my head when I saw that.
I'll be checking for fuel starvation and governor today. I have a different carb on the way.

Two cents appreciated!