Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Farmall & IHC Tractors Discussion Forum
:

F-20 missing - - continuing saga

Welcome Guest, Log in or Register
Author 
Pete L

06-14-2004 19:51:03




Report to Moderator

Guys - - Spent part of Sunday and this evening working on my F-20 that I wrote to you about on Friday. Intake system proves tight with no leaks. Carb was dismantled and all passages rechecked and float level checked. Valve and spark timing proves right on. Curious about a note about replacing the valve springs that was sent in. After all the work this past year, the springs are one of the few things that have remained a constant. Shouldn't I be able to shim up the springs with slit washers to prove this theory?

Had it back together and running tonight, and it still misses like it did when first bought, but lean into a 4x4 on the PTO pulley and with the spark fully advanced, it sounds great, like it always had.

Any other words of wisdom out there? I just seems like it isn't getting gas uniformly to the cylinders when running at no load and spark fully advanced, as there's no black smoke like from an unburned mix or burning rich.

We had a theory that with the shared intake passages of cylinders 1&2 and 3&4, that if an intake valve were to be late closing, especially during a spark advanced condition, the explosion from one cylinder could be leaking into the intake draw from the second cyliner and flashing off that gas, as I still hear a slight popping in the carburator as it is missing. Could this be the valve springs?

Thanx for your words of support and encouragement.

[Log in to Reply]   [No Email]
kfox

06-16-2004 12:37:37




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
I vote for a worn lobe on the cam. Not raising enough a low speed, but gets a little better when you wind her up some...less you all ready checked the cam lobes. Hope you find the old girls problem. Ken



[Log in to Reply]  [No Email]
Hermit

06-15-2004 18:44:34




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
If you still have 10-12 in. vacuum, that still indicates late valve timing. Are you checking the valve timing by looking at the index marks on the timing gear and the crankshaft or are you using a protractor on the crank and watching the valves?



[Log in to Reply]  [No Email]
Farmall450man

06-15-2004 07:42:31




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
Pete, spent many hours on a '39 F-20. It should idle better than you have described. I know that you swapped out the mag from a good running tractor witout affect. But I keep thinking that it sounds like irregular spark delivery/advance at low rpm. When you check the timing do you get any movement of the timing? You would have to watch it close to see if this is happening.



[Log in to Reply]  [No Email]
lee

06-15-2004 13:44:11




Report to Moderator
 Re: Re: F-20 missing - - continuing saga in reply to Farmall450man, 06-15-2004 07:42:31  
I think Farmall450 may have a point to look at. Check the rotor is tightly keyed to the shaft. Mine had significant slop on the plastic rotor key to the shaft. A mag can be a loose goose in some ways with many moving parts making the spark timing something less than rock solid.



[Log in to Reply]  [No Email]
brianh

06-15-2004 07:31:12




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
Did you ever narrow the missing down to a particular cylinder or cylinders?
The valve springs are easy to check with the engine running... put a screwdriver between the coils and turn it to tighten the spring up.
My '37 F-20 idles fine, so I don't agree that they all idle rough. It runs a little rich at idle, but I have to set it that way so it will pick up a load OK. It's a kero carburetor, so I expect it to run a little rich.
Brian

[Log in to Reply]  [No Email]
pg

06-15-2004 03:12:04




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
you sure youve got the carb adjusted correctly? have you checked the govenor? pg



[Log in to Reply]  [No Email]
Pete L

06-15-2004 06:49:59




Report to Moderator
 Re: Re: F-20 missing - - continuing saga in reply to pg, 06-15-2004 03:12:04  
The carb has been adjusted in every which way. As far as the govenor, I have tried detaching it from the carb and holding the shaft still with my fingers. Missing is still there, so I've ruled out the govenor as a contributor. Thanks for the thoughts though.



[Log in to Reply]  [No Email]
Pale Rider

06-14-2004 22:32:27




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
While I don't claim to be an expert and my own is not running at this point, I have always had the understanding that it was fairly common for the F-20s to miss at idle and then correct out under full load. I wonder in fact if you are not chasing around a problem that is simply inherent to the design and for which there is no solution. You may be frustrating yourself to no purpose. It sounds to me like you have a nice tractor in every other detail. I wonder if you shouldn't just consider it to be completed and part of its character and charm.

[Log in to Reply]  [No Email]
nebraska cowman

06-15-2004 02:46:52




Report to Moderator
 Re: Re: F-20 missing - - continuing saga in reply to Pale Rider, 06-14-2004 22:32:27  
I'm with pale rider. Kinda the nature of the beast



[Log in to Reply]  [No Email]
lee

06-14-2004 20:20:54




Report to Moderator
 Re: F-20 missing - - continuing saga in reply to Pete L, 06-14-2004 19:51:03  
How did you verify the valve and ignition timing?



[Log in to Reply]  [No Email]
Eric

06-14-2004 21:06:19




Report to Moderator
 Re: Re: F-20 missing - - continuing saga in reply to lee, 06-14-2004 20:20:54  
The motor in mine gave up on fri evening long story its fixable and will get fixed mine sounded perfect befor it went all i really have to say is the look at it this way the tractor is 68 years old cut it some slack if you do figure it out then we'll all be glad for you but till that comes think of it ans being an old man when it gets old it starts forgetting things maybe its forgetting t fire everytime you know what im trying to say i hope Eric

[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy