[AT] Tractor Question - 420 JD

Fri Aug 8 21:45:14 PDT 2008

Dean,  I tend to agree with you on the carb being the culprit.  If for no 
other reason than that I chased the same problem on a tractor with a MS carb 
for a few days and was certain that the carb was ok when it turned out to be 
the culprit.  Like you said, without actually laying hands on the tractor 
and hearing it run it's hard to know.

Charlie
----- Original Message ----- 
From: "Dean Van Peursem" <deanvp at att.net>
To: "'Antique tractor email discussion group'" 
<at at lists.antique-tractor.com>
Sent: Friday, August 08, 2008 10:50 PM
Subject: Re: [AT] Tractor Question - 420 JD

> Paul,
>
> It is good to consider all possible causes for the problem but the 
> symptoms you
> have described are classical JD carburetor problems which are, 99% of the 
> time,
> plugged passages(s) in the carburetor. A partial choking will not make up 
> for
> the lack of gas feeding to the carburetor due to something plugging the 
> supply
> lines. A partial choking WILL make up for a passage NOT PROVIDING THE 
> PROPER
> FEED INTERNALLY within the carburetor. Choking cannot provide more gas if 
> there
> isn't enough gas being supplied by the external lines. The only other
> possibilities are that the float is set too low or you have an external 
> intake
> manifold leak, intake manifold gasket leak or partial manifold blockage. 
> The
> supply line can be easily checked for blockage by disconnecting the line 
> at the
> carburetor inlet and checking its flow rate. The tank doesn't have to be 
> removed
> to check the flow rate.  Just trying to save you from chasing other
> possibilities and all the associated work.
>
> One test that would be of real value if you know someone who has a similar
> tractor. Swap carburetors and see if the problem follows the carburetor. 
> I'm
> willing to bet a large quantity of M & M's that the problem is the 
> carburetor.
> If I could touch and feel and hear the tractor myself to personally 
> observe the
> symptoms, I'd probably change the bet from M & M's to dollar bills.
>
>
> Dean Van Peursem
> Snohomish, WA
>
> If we take the time to count our blessings we don't have time to complain.
>
>
>
> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com
> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Paul Waugh
> Sent: Friday, August 08, 2008 5:58 PM
> To: Antique tractor email discussion group
> Subject: Re: [AT] Tractor Question - 420 JD
>
> OK, one thing I have learned about this list is pay attention.  I have 
> never
> had the tank off. I feel that I have a good flow and get very little
> sediment in the bowl. BUT, because of several replies, I will pull the 
> tank.
> First I will try the LP gas trick.
> OH, the first thing is pull it up a good hill, winch in onto the trailer,
> and bring it home. Right now it is sitting in a 3 acre bottom ground that
> has not been touched for years, mainly because of the hill.  This land, my
> son just bought, no electric, nothing but a good hay field, and more than
> several walnut trees, 12-24 in in diameter.
>
> Paul in IN
>
> ----- Original Message ----- 
> From: "charlie hill" <chill8 at suddenlink.net>
> To: "Antique tractor email discussion group" 
> <at at lists.antique-tractor.com>
> Sent: Friday, August 08, 2008 5:21 PM
> Subject: Re: [AT] Tractor Question - 420 JD
>
>
>> Paul are you sure you don't have fuel supply problems?  You need to check
>> your tank and fuel lines carefully.  Sometimes a piece of debris will 
>> hang
>> around the tank outlet.  The fuel flow will pull it down over the 
>> opening.
>> When you stop for a while it will float free.
>>
>> Good luck.  Those sorts of problems can run a guy crazy.
>>
>> Charlie
>> ----- Original Message ----- 
>> From: "Paul Waugh" <pwaugh at embarqmail.com>
>> To: "Antique tractor email discussion group"
>> <at at lists.antique-tractor.com>
>> Sent: Friday, August 08, 2008 2:42 PM
>> Subject: Re: [AT] Tractor Question - 420 JD
>>
>>
>>>I just got back from trying my "cleaning' ... no different, run 3-4 sec
>>>then
>>> quit.  I had heard of the WD-40 method, but I will try the LP gas method
>>> ...
>>> as soon as I get it drug up from the bottom of a hill to up under a 
>>> shade
>>> tree, and can charge battery or jump battery hahaha
>>>
>>> Thanks a bunch for ideas and help
>>>
>>> Paul in IN
>>> ----- Original Message ----- 
>>> From: "Mike Sloane" <mikesloane at verizon.net>
>>> To: "Antique tractor email discussion group"
>>> <at at lists.antique-tractor.com>
>>> Sent: Friday, August 08, 2008 6:54 AM
>>> Subject: Re: [AT] Tractor Question - 420 JD
>>>
>>>
>>>> Instead of WD-40, these days I use an unlit propane torch with the 
>>>> valve
>>>> cracked open. That way you can direct the propane right at the various
>>>> points around the manifold and the carburetor. In addition to warping,
>>>> look for pinholes in the casting and gaskets that aren't sealed
>>>> completely. You need to cover the entire area of the intake from the
>>>> head to the carburetor, including the throttle shaft itself. A worn
>>>> throttle shaft/bushings will allow air to get past and cause a lean
>>>> mixture.
>>>>
>>>> Mike
>>>>
>>>> Lew Best wrote:
>>>>> Don't know if it'll still work as I'm told that WD40 has been
>>>>> re-formulated but in the old days you could spray it around the
>>>>> manifold
>>>>> contact places, etc. with an engine running & any vacuum leak would
>>>>> make
>>>>> an engine speed up quite noticeably.  Ether starting fluid should do
>>>>> the
>>>>> same but would have to be kept plenty far from the carb intake to 
>>>>> avoid
>>>>> a "false alarm."
>>>>>
>>>>> Lew
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>>
>>>>> Thanks for the replies.  It is good to know that at least it is the
>>>>> right
>>>>> one.  I have cleaned with carb cleaner and blown out several times 
>>>>> over
>>>>> the
>>>>> 15 years I have owned it.. I took it to the place that Dennis Polk
>>>>> uses,
>>>>> and
>>>>> had it boiled and new jets, still same thing.  I had heard of the 
>>>>> place
>>>>> in
>>>>> IA and was thinking of trying them.  About a vacuum leak, I did a ring
>>>>> job 2
>>>>> years ago, and used all new gaskets, so it should not be leaking air. 
>>>>> I
>>>>> did
>>>>> use the same manifold, so if it is wrapped, then I would have the same
>>>>> problem.
>>>>>
>>>>> I will keep plugging away, thanks again
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
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