420 sputtering and backfireing
420 sputtering and backfireing
before we brought our new crawler home it purred like a kitten, now.. not so much it just sputters and spits and backfires... the only thing that changed was it was in the high desert and we hauled it 300 miles to the valley floor. now like i said it backfires like crazy and only runs with the choke on, we had the carb rebuilt thinking that was the problem. but it still doesn't want to run right. could somthing have come loose while hauling it home? distributor cap is what we're thinking to replace next, maybe plugs?
thanks for any info in advance
thanks for any info in advance
If it only runs with the choke on, it is lean for some reason. Did you set the load jet after you rebuilt the carb?
Lavoy
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com
Owner and moderator www.jdcrawlers.com
- Willyr
- 2010 crawler
- Posts: 695
- Joined: Sat Jul 17, 2010 3:03 am
- Location: Downeast Maine (North of Ellsworth)
You have a vacuum leak some where as a possibility as well. Easiest way to check for vacuum leak. After it has started, use some wd-40 or some form of aerosol lubricant. Spray around the gasket surfaces. If the engine rpm changes while spraying in a area you have found your leak.
I did have something on my 60 that bothered my tractor as well. It backfired up a storm comming down a hill when using it for a people mover. On mine on of the valve adjusters had broken and I had a 0.250" clearance on a exhaust valve. Just a thought to check. Once it was back to the correct setting my tractor no longer even rumbles.
Only other item is heat. On the desert it may have been warmer than down on the valley floor. Castings may have made for tighter joints. Again it would be a vacuum leak.
I did have something on my 60 that bothered my tractor as well. It backfired up a storm comming down a hill when using it for a people mover. On mine on of the valve adjusters had broken and I had a 0.250" clearance on a exhaust valve. Just a thought to check. Once it was back to the correct setting my tractor no longer even rumbles.
Only other item is heat. On the desert it may have been warmer than down on the valley floor. Castings may have made for tighter joints. Again it would be a vacuum leak.
former owner of a 1956 420c
All help is greatly appreciated.
Proud owner of a project 1952 JD 60
http://www.youtube.com/watch?v=nFehqXVd9z4
All help is greatly appreciated.
Proud owner of a project 1952 JD 60
http://www.youtube.com/watch?v=nFehqXVd9z4
- gregjo1948
- 350 crawler
- Posts: 1000
- Joined: Mon Aug 30, 2010 5:58 am
- Location: Newark Valley,NY,USA
420 Sputtering
Too much air--not enough fuel. But why the backfiring? I'd check ignition timing, check for fuel flow ubstuction, then adjust carb. Greg
JD 350B diesel 6way blade, Case 580B Loader/backhoe, Farmall 504 high crop w/ flail boom mower, International 404 , International 284 diesel w/belly mower, 1972 Ford F600 dump truck, Galion 3-5 roller, Allis Chalmers D17, 1620 Ford
Done it on 6 volts, would never do it again, way to irratating to start. On 12, would not be an issue.
Lavoy
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com
Owner and moderator www.jdcrawlers.com
-
- 1010 crawler
- Posts: 353
- Joined: Mon Apr 04, 2005 6:53 pm
- Location: Columbus Ohio
- Willyr
- 2010 crawler
- Posts: 695
- Joined: Sat Jul 17, 2010 3:03 am
- Location: Downeast Maine (North of Ellsworth)
I used the electronic points on my 420. Loved it for certain. Cost is high, but you can guaranty ignition.
If I had the money again I would get a set for my 60
If I had the money again I would get a set for my 60
former owner of a 1956 420c
All help is greatly appreciated.
Proud owner of a project 1952 JD 60
http://www.youtube.com/watch?v=nFehqXVd9z4
All help is greatly appreciated.
Proud owner of a project 1952 JD 60
http://www.youtube.com/watch?v=nFehqXVd9z4
I have three gas JD440s with original design 6 volt ignition components that I run every month. One revolution of the engine and they all start immediately. My point is that there is nothing wrong with the original design. You can change to 12 volts, or move to electronic ignition, or make other modifications that suit you; but don't do it because you think that somehow the old 6 volt system never worked well. Gil
JD440-ICD loader; JD440-IC bulldozer; JD440-ICD backhoe; JD440-I backhoe; JD440-I tractor; + five recumbent JD440-ICs
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