Symptoms of worn distributor ?

JohnDeereJimOhio · Apr 3, 2014

I have been battling are John Deere 420c Crawler for a few weeks now. Problems started with a stuck valve and bent push rod. I got everything fixed up and then thought I had carb problems but turned out to be electrical issues. Anyway got it running and it sounds better than it ever has, however it runs good for around 30-45 seconds then starts to break up and run rough. Fuel flow is good and carb was just rebuilt. I am wondering if these symptoms could be caused by a worn distributor. The distributor on this crawler has much more play than the one in my G... Anyone had experience with this?

Bob · Apr 3, 2014

It would take a few seconds with an ignition oscilloscope to see what's going on, but I'm guessing you don't have access to one.

While worn distributor bushings are not a good thing, I DOUBT they are causing the problem you are seeing.

I would suspect a fuel issue, or possibly a "thermal" coil or condenser.

As a "down and dirty" test to see if the shaft play is causing your problem, you could try increasing the point gap a few thousandths, then decreasing it a few thousandths. If one way or the other makes it run better, that would tend to point to lots of shaft movement and when the housing warms up and expands a bit, along with the wobble, the changed point gap gets out of the range in which the points will close, then open up to create a spark.

A "

Mike M · Apr 3, 2014

If JD still sells that bushing I'd put one in anyhow since you know it's worn.
I have seen improper point gap mimic a fuel flow problem in a JD 212 lawn mower.

el6147 · Apr 3, 2014

I had the same problem on my 440c this week , thought it was a fuel or carb issue , and then relaced the points, rotor and condensor with no change and it turns out there was a poor connection at the distributor on the power wire.

I would still rebuild the distributor, a sloppy shaft will make a engine run hot and poorly.

Ultradog MN · Apr 3, 2014

Another cure for worn bushings is electronic ignition.

keh · Apr 3, 2014

Had somewhat similar symptoms on a JD 2010 and it turned out to be the ignition switch. New switch solved problem. don't remember how you check for a bad switch.

KEH

redtom · Apr 3, 2014

Friend chased that on a Farmall C and it ended up being a bad condenser

schrade · Apr 3, 2014

Not a tractor but a 427 chevy truck engine. the distributor had too much play in it that it was hard to start and would not idle well. At high rpm it ran ok. Put in new distributor was all well.

4play · Apr 3, 2014

The distributor in my 8N was so worn that I could open and close the points by wiggling the top of the shaft. The adv weights were also loose and would fling out at the slightest turning motion, I was suprised that they actually moved. The odd thing was the engine ran like a top with the only complaint being a single cylinder misfire at very random times which is probably not related anyway.

I just replaced this distributor though, it seems that sometime in the past a previous owner dropped a screw for the points down under the breaker plate and it finally found wedged between the weights and case. This caused the distributor to lock up and spin around until the engine stopped, Im kind of glad the hold down clamp was not real tight. Im not sure if the plug wires are still good yet but the spinning distributor had then wound up pretty tight.

old bc · Apr 3, 2014

I had a houseboat with a 318 Chrysler engine that would idle fine and rev up to 4500 but if you put it in gear it would miss at about 2000 RPM's. It turned out to be worn bushings. I had the distributor rebuilt. Problem solved.

Hendrik · Apr 4, 2014

Checking for a bad switch can be done by hot wiring the coil from the ungrounded battery post.
HTH

Symptoms of worn distributor ?

JohnDeereJimOhio

Member

Bob

Well-known Member

Mike M

Well-known Member

el6147

Member

Ultradog MN

Well-known Member

keh

Well-known Member

redtom

Well-known Member

schrade

Member

4play

Well-known Member

old bc

Member

Hendrik

Member

Similar threads