carb problem
Re: carb problem
per chance is there an economiser jet in that carb, I have had to drill the jet a lttle bigger on one i had a problem with ????
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- 420 crawler
- Posts: 38
- Joined: Sat Sep 23, 2006 12:20 pm
- Location: Columbus, Ohio
Re: carb problem
I had the same problem with a marvel-sheibler carburetor on a different make of crawler. Since you had the carburetor apart, is the venturi removable? The problem I had is sealer is needed where the venturi seats. The area around the venturi vents to the atmosphere, so if it is not properly sealed, it makes a large vacuum leak, requiring the choke to be applied to provide sufficient fuel.
1960 440 ICD with 602 blade
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle
Re: carb problem
Given the age of the machine, there is a good chance the carb has been apart several times. Is it possible a prior owner could have lost some vital piece(s) or put in some off pieces(say from another carb, tractor etc). Going through a exploded parts break down with a fine tooth comb maybe a good idea, also.
- gregjo1948
- 350 crawler
- Posts: 1000
- Joined: Mon Aug 30, 2010 5:58 am
- Location: Newark Valley,NY,USA
Re: carb problem
I don't think it would be ignition problem if choking it helps its performance. That's why I'm thinking lack of compression or just a simple vacuum leak.B Town wrote: ↑Mon Oct 22, 2018 5:41 amIf the fuel and carb system are up to spec as you have discussed, I would start to troubleshoot the ignition. It has been my experience that many a problem blamed on the carb were actually ignition system problems, condenser, points, etc..
I think the compression test is a great idea, also.
I agree with the air cleaner blockage causing a fuel rich situation. But when focused on a problem that doesn't seem to be getting better with your intervention it is time to step back and take a wider POV.
Best regards, Bruce
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
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- 420 crawler
- Posts: 26
- Joined: Sun Oct 21, 2018 9:57 am
- Location: Northern Minnesota
Re: carb problem
Yellowcrawler, the venture is removable. What type of sealer are you talking about? B Town, all of the correct parts are there. Compression is good and there are no vacuum leaks. I'm going to try another coil today to see if that makes any difference. Thanks to everyone for their replies.
Re: carb problem
No drill bit access, but dental tools will get in some of them, torch tip cleaners as well. Once you have it all apart, you can take carb cleaner spray with the tube on it, and hold the end of the tube against pretty much all of the passages and make sure that they are open.
Make sure float level is correct, no damage in the jets, all the little holes in the long load nozzle are open, etc.
Lavoy
Make sure float level is correct, no damage in the jets, all the little holes in the long load nozzle are open, etc.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com
Owner and moderator www.jdcrawlers.com
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- 420 crawler
- Posts: 26
- Joined: Sun Oct 21, 2018 9:57 am
- Location: Northern Minnesota
Re: carb problem
Thanks for the input again, Lavoy. I've already done what you just suggested - all passages will flow brake clean through them and the holes in the nozzle are open and clear. Just tried a different coil but there was no change. Have you heard about the venture having to be sealed with some kind of sealer?
Re: carb problem
No, no need for sealer.
What happens if you open the load jet a half turn or so, that should eliminate the need for choke assuming all else is good. If not, still something wrong internally.
Lavoy
What happens if you open the load jet a half turn or so, that should eliminate the need for choke assuming all else is good. If not, still something wrong internally.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com
Owner and moderator www.jdcrawlers.com
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- 420 crawler
- Posts: 26
- Joined: Sun Oct 21, 2018 9:57 am
- Location: Northern Minnesota
Re: carb problem
I can back out the load needle until it is ready to fall out and still have to run it with choke under load.
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- 420 crawler
- Posts: 38
- Joined: Sat Sep 23, 2006 12:20 pm
- Location: Columbus, Ohio
Re: carb problem
I believe I used permatex aviation gasket sealer. I used it in the past for Volkswagen engine cases and it worked great, I still have the same can from over 40 years ago! I wanted to use something impervious to gasoline but removable in case I needed to take it apart again. When you take the carburetor apart, look real close around the venturi when you pull it out. I believe it has a machined groove or step in it. Going totally off memory right now, (this was 13 years ago) the body gasket fits in this step, but it has a slight gap between the venturi and the cast iron body. If you trace the cavity around the venturi out, you will find that it ties to the vent.
I will try to find a diagram of the carburetor. I think I sealed both top and bottom of the venturi to the body and waited a little while, then put the bowl gasket on, put the carburetor together and waited a day for the permatex to take a good set. I fought this thing for several months, so I finally traced everything out, discovered the venturi needed sealing and it ran like a new one. I had put in new rings, had the head done, plugs, wires points, etc. and was real disappointed that I needed to choke it about halfway for it run without stalling. I could tell it was lean. Nothing helped until I found this real simple item with the venturi. I have helped a few others that had the same issue, just takes a little time and some sealer.
I will try to find a diagram of the carburetor. I think I sealed both top and bottom of the venturi to the body and waited a little while, then put the bowl gasket on, put the carburetor together and waited a day for the permatex to take a good set. I fought this thing for several months, so I finally traced everything out, discovered the venturi needed sealing and it ran like a new one. I had put in new rings, had the head done, plugs, wires points, etc. and was real disappointed that I needed to choke it about halfway for it run without stalling. I could tell it was lean. Nothing helped until I found this real simple item with the venturi. I have helped a few others that had the same issue, just takes a little time and some sealer.
1960 440 ICD with 602 blade
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle
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- 420 crawler
- Posts: 38
- Joined: Sat Sep 23, 2006 12:20 pm
- Location: Columbus, Ohio
Re: carb problem
https://www.scribd.com/doc/60666720/Mar ... air-Manual
Figure S-17 from the webpage above shows the venting around the venturi.
Figure S-17 from the webpage above shows the venting around the venturi.
1960 440 ICD with 602 blade
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle
- gregjo1948
- 350 crawler
- Posts: 1000
- Joined: Mon Aug 30, 2010 5:58 am
- Location: Newark Valley,NY,USA
Re: carb problem
I don't understand how it could be an ignition or electrical problem. How does it help performance when it's choked if it's an ignition problem? When you choke it, does it richen the fuel/air mixture enough to produce dark or black smoke from the exhaust? Have you shot carb cleaner thru the carb at full throttle while choking it? I've had luck doing that but , I had to do it several times before it loosened the blockage. I wish you'd figure this problem out 'cause I think I might learn something.
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
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- 420 crawler
- Posts: 26
- Joined: Sun Oct 21, 2018 9:57 am
- Location: Northern Minnesota
Re: carb problem
yellowcrawler, thanks for the post. The link you gave leads to the carb manual that I downloaded and printed when I started working on this problem. At this point I'm willing to try anything so later today I'm going to try sealing the venture and see if that helps. To recap, the compression is good ( 120 - 125 each cylinder ) , valves set, no vacuum leaks, air filter serviced, new plugs, points cleaned and adjusted, tried different coil, and carb disassembled and cleaned several times. I'll keep everyone posted but in the mean time, if anyone has any more suggestions feel free to post.
Re: carb problem
If the venturi is leaking, it is damaged. The venturi is a "press" fit for lack of a better term. The flanges on each end of the venturi seat on a ledge in each half of the carb. When the carb is assembled, the venturi is slightly longer than the distance between these two ledges, so it is compressed. This is all that is necessary to make it seal. I have done I would guess a hundred of these carbs, never has the venturi been the problem except for the one I left it sitting on the bench instead of putting it back in the carb. Deere does not say anything about gluing the venturi in in the carb manual.
Install the venturi without the carb body gasket gently and see if the two halves don't want to completely go together.
Someone in the past has installed the wrong parts, damaged some parts, or some other problem that is not your fault. These carbs are not rocket science, but sometimes small things can really goof them up. I have rebuilt more than a few "rebuilt" or 'just kitted" carbs over the years, so it would not surprise me. The problem is definitely carb somewhere, not ignition.
Lavoy
Install the venturi without the carb body gasket gently and see if the two halves don't want to completely go together.
Someone in the past has installed the wrong parts, damaged some parts, or some other problem that is not your fault. These carbs are not rocket science, but sometimes small things can really goof them up. I have rebuilt more than a few "rebuilt" or 'just kitted" carbs over the years, so it would not surprise me. The problem is definitely carb somewhere, not ignition.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com
Owner and moderator www.jdcrawlers.com
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- 420 crawler
- Posts: 26
- Joined: Sun Oct 21, 2018 9:57 am
- Location: Northern Minnesota
Re: carb problem
When my carb is all together the venture will not move, so I assume that it is sealing. I sent you a P.M.
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