carb problem

General help and support for your Lindeman through 2010 John Deere crawler
boler76
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Re: carb problem

Post by boler76 » Mon Oct 22, 2018 2:42 pm

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 ????

yellowcrawler
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Re: carb problem

Post by yellowcrawler » Mon Oct 22, 2018 5:03 pm

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

B Town
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Re: carb problem

Post by B Town » Mon Oct 22, 2018 9:11 pm

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.

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gregjo1948
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Re: carb problem

Post by gregjo1948 » Tue Oct 23, 2018 5:24 am

B Town wrote:
Mon Oct 22, 2018 5:41 am
If 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
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.
JD 350B diesel w/rops & 6way blade, Case 580B Loader/backhoe, Farmall 504 highcrop, International 404 utility, International 284 diesel w/belly mower, 1972 Ford F600 dump truck, Galion 3-5 roller

mnfordtech
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Re: carb problem

Post by mnfordtech » Tue Oct 23, 2018 5:42 am

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.

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Lavoy
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Re: carb problem

Post by Lavoy » Tue Oct 23, 2018 9:06 am

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.
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mnfordtech
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Re: carb problem

Post by mnfordtech » Tue Oct 23, 2018 10:32 am

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?

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Lavoy
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Re: carb problem

Post by Lavoy » Tue Oct 23, 2018 12:53 pm

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.
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mnfordtech
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Re: carb problem

Post by mnfordtech » Tue Oct 23, 2018 2:34 pm

I can back out the load needle until it is ready to fall out and still have to run it with choke under load.

yellowcrawler
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Re: carb problem

Post by yellowcrawler » Tue Oct 23, 2018 5:19 pm

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.
1960 440 ICD with 602 blade
1960 440 ICD with 831 bucket
1960 440 ICD with 831 bucket, center throttle

yellowcrawler
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Re: carb problem

Post by yellowcrawler » Tue Oct 23, 2018 5:24 pm

https://www.scribd.com/doc/60666720/Mar ... air-Manual

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

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gregjo1948
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Re: carb problem

Post by gregjo1948 » Wed Oct 24, 2018 4:04 am

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 w/rops & 6way blade, Case 580B Loader/backhoe, Farmall 504 highcrop, International 404 utility, International 284 diesel w/belly mower, 1972 Ford F600 dump truck, Galion 3-5 roller

mnfordtech
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Re: carb problem

Post by mnfordtech » Wed Oct 24, 2018 4:58 am

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.

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Lavoy
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Re: carb problem

Post by Lavoy » Wed Oct 24, 2018 8:58 am

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.
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mnfordtech
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Re: carb problem

Post by mnfordtech » Wed Oct 24, 2018 11:31 am

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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