to-30 random miss fire

[steve-in-ga]

my to-30 has a random miss that I'm trying to fix. Spark plugs aren't foiled, coil is good, plug wires aren't shorting to ground and I can't find an air leak anywhere. It has an electronic ignition so points and condenser aren't an issue. What are some not so obvious things that can cause a random miss. It misses when its cold and at operating temp.

 

[6 SLY PLACE]

Check your ignition timing or maybe your valves need adjusting

 

[olddavid]

(quoted from post at 06:38:01 11/23/23) my to-30 has a random miss that I'm trying to fix. Spark plugs aren't foiled, coil is good, plug wires aren't shorting to ground and I can't find an air leak anywhere. It has an electronic ignition so points and condenser aren't an issue. What are some not so obvious things that can cause a random miss. It misses when its cold and at operating temp.

Just because it has electronic ignition I wouldn't totally eliminate it from suspicion.

 

[Hdonly]

Possibly worn out bushings in distributor allowing the shaft to wobble too much?

This post was edited by Hdonly on 11/23/2023 at 08:30 am.

 

[Jim L WA]

How bad is it? One single misfire or a series of them? Like Olddavid said, it still could be ignition, but I would suspect valve seating. You could do a compression test.

 

[steve-in-ga]

Sometimes one miss other times multiple
misses in a row.

 

[olddavid]

(quoted from post at 10:04:24 11/23/23) How bad is it? One single misfire or a series of them? Like Olddavid said, it still could be ignition, but I would suspect valve seating. You could do a compression test.

Agree. The valves could be sticking in the guides. That could happen randomly. Unfortunately, lots of possibilities.

 

[John Deere D]

With engine running,attach a strobe lite,....check each plug wire.....

 

[rustred]

It can be as simple as a bad spark plug. And usually is when it a randem miss.

 

[RM-MN]

Another possible cause is an ignition switch or an ammeter going bad. Being intermittent those kind of issues are hard to diagnose.

 

[Jim L WA]

(quoted from post at 06:22:10 11/24/23) Another possible cause is an ignition switch or an ammeter going bad. Being intermittent those kind of issues are hard to diagnose.

The ignition switch and ammeter can be eliminated by jumpering past them and see if the problem persists. Other than that you may just have to wait for it to get worse before you can pin it down. Be careful that you don't throw a bunch of parts at it and still not fix it.

 

[Bruce(OR)]

Well if your in Ga, then in about another 5 hours you can try the magic diagnostic tool.
Fire it up tonight and look for spark bouncing around in the dark