MC Hunting for an idle
- MountainHighMC
- 40C crawler
- Posts: 19
- Joined: Tue May 13, 2014 9:27 pm
- Location: Southern Interior BC
MC Hunting for an idle
Hey guy's, so my ol gal has decided to take up an erratic idle, it isn't a major by any means but nonetheless apparent.
I went through the carb, installed a basic kit and load adjustment assy still up and down ever so slightly.
Checked ign timing and found it to be all over the map as well...
The engine has always taken it's time to come down to low idle when the throttle position is decreased. I managed to improve on that somewhat today.
I'm certain the motor has a bazzillion hours on it but would like it to run as well as possible.
Any suggestions on probable causes is appreciated.
Regards
Bradley
I went through the carb, installed a basic kit and load adjustment assy still up and down ever so slightly.
Checked ign timing and found it to be all over the map as well...
The engine has always taken it's time to come down to low idle when the throttle position is decreased. I managed to improve on that somewhat today.
I'm certain the motor has a bazzillion hours on it but would like it to run as well as possible.
Any suggestions on probable causes is appreciated.
Regards
Bradley
- gregjo1948
- 350 crawler
- Posts: 1000
- Joined: Mon Aug 30, 2010 5:58 am
- Location: Newark Valley,NY,USA
Check the distributor shaft for bad bushing. If the bushing is worn, there will be varying point gap causing incorrect timing. gregjo1948
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
- DukeofDeere
- 1010 crawler
- Posts: 443
- Joined: Wed Oct 26, 2011 7:12 am
- Location: Hudsonville Michigan
- Stan Disbrow
- 350 crawler
- Posts: 2904
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
Let us give him something else. The governor is sticky. Which would cause the slow rev down to idle after the lever is moved. You know, the lever which goes to the governor and not the carb....
My M did that last spring. Started running oddly and surging at idle. Governor and linkages wanted some lubing up. What?(!) after 60 years! Sheesh!
Stan
Let us give him something else. The governor is sticky. Which would cause the slow rev down to idle after the lever is moved. You know, the lever which goes to the governor and not the carb....
My M did that last spring. Started running oddly and surging at idle. Governor and linkages wanted some lubing up. What?(!) after 60 years! Sheesh!
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
- MountainHighMC
- 40C crawler
- Posts: 19
- Joined: Tue May 13, 2014 9:27 pm
- Location: Southern Interior BC
- MountainHighMC
- 40C crawler
- Posts: 19
- Joined: Tue May 13, 2014 9:27 pm
- Location: Southern Interior BC
Afternoon, well I checked that distributer shaft for play, yes there is.
I also noticed that the governor lever comes into contact with the air cleaner mounting bracket before it hits the governor stop screw...
Funny thing is that she only revved about sixteen hundred rpm at high idle?..
Any ideas?
Anyways, I decided to remove the rad and fan assembly so as to try and repair a very feeble previous attempt at repairing a cracked water jacket on the head.
Hey Stan, were you meaning that I should remove, clean and inspect the governor assembly then lube and reinstall?
Regards
Bradley
I also noticed that the governor lever comes into contact with the air cleaner mounting bracket before it hits the governor stop screw...
Funny thing is that she only revved about sixteen hundred rpm at high idle?..
Any ideas?
Anyways, I decided to remove the rad and fan assembly so as to try and repair a very feeble previous attempt at repairing a cracked water jacket on the head.
Hey Stan, were you meaning that I should remove, clean and inspect the governor assembly then lube and reinstall?
Regards
Bradley
- Stan Disbrow
- 350 crawler
- Posts: 2904
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
Well, the gov should have lube in it. After so many years, is there any left, and what does it look like is a good question. The linkage tends to get lubed by the 'fire a blob' method. Most of it you can see, but can be hard to get an oil can tube to. Then, what was in the oil can becomes another good question. Something that attracts dirt, usually.
Anyway, it all tends to get sticky over time. A little stick there, a little hang-up there, and one day it acts up. Cranky old iron!
Stan
Well, the gov should have lube in it. After so many years, is there any left, and what does it look like is a good question. The linkage tends to get lubed by the 'fire a blob' method. Most of it you can see, but can be hard to get an oil can tube to. Then, what was in the oil can becomes another good question. Something that attracts dirt, usually.
Anyway, it all tends to get sticky over time. A little stick there, a little hang-up there, and one day it acts up. Cranky old iron!
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
- gregjo1948
- 350 crawler
- Posts: 1000
- Joined: Mon Aug 30, 2010 5:58 am
- Location: Newark Valley,NY,USA
I think the MC runs at low rpms. 1600 might be where it should be. gregjo1948
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
MC should be 1800 at high idle, loaded speed is 1650.
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
- MountainHighMC
- 40C crawler
- Posts: 19
- Joined: Tue May 13, 2014 9:27 pm
- Location: Southern Interior BC
Mornin boy's
So I removed the governor, found that the lower dowel pin was made out of an ole piece a wood, also that the weight arms had been coming into contact with the front gear cover due to a worn nose cone bushing in the cover. Also that the gov drive gear has a few chipped teeth... (Not a major I'm sure)
I put her all back together and we took er up to my buddy's farm, graded out some high spots in his driveway, and proceeded to tend to the burn pile.
I was halfway across the riding ring and all of a sudden she started running really rich, smokin like a house on fire, unresponsive to any carb adjustments, and barely keep running at all.
I shut the gas off and gave her a bit to settle down and she fired back up, but now she is way down on power and running very rough. Still got the job done but is showing a lot of emotion, I know she's old and cranky but any help is appreciated
Regards
Bradley
So I removed the governor, found that the lower dowel pin was made out of an ole piece a wood, also that the weight arms had been coming into contact with the front gear cover due to a worn nose cone bushing in the cover. Also that the gov drive gear has a few chipped teeth... (Not a major I'm sure)
I put her all back together and we took er up to my buddy's farm, graded out some high spots in his driveway, and proceeded to tend to the burn pile.
I was halfway across the riding ring and all of a sudden she started running really rich, smokin like a house on fire, unresponsive to any carb adjustments, and barely keep running at all.
I shut the gas off and gave her a bit to settle down and she fired back up, but now she is way down on power and running very rough. Still got the job done but is showing a lot of emotion, I know she's old and cranky but any help is appreciated
Regards
Bradley
- gregjo1948
- 350 crawler
- Posts: 1000
- Joined: Mon Aug 30, 2010 5:58 am
- Location: Newark Valley,NY,USA
- DukeofDeere
- 1010 crawler
- Posts: 443
- Joined: Wed Oct 26, 2011 7:12 am
- Location: Hudsonville Michigan
- MountainHighMC
- 40C crawler
- Posts: 19
- Joined: Tue May 13, 2014 9:27 pm
- Location: Southern Interior BC
- BradE
- 40C crawler
- Posts: 15
- Joined: Tue Apr 03, 2012 11:00 am
- Location: Northeast Kingdom of Vermont
Float ?
Same thing happened to my last 40C. Float had leaked, was full of gas. Flooded out. Let it sit, restarted OK until next time. Got a new float and never had the problem again.gregjo1948 wrote:Maybe a float problem. gregjo1948
JD 40C 4 roll 1955, snow tracks and sprockets from a 350
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