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

Shop Now

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

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Discussion Forum
:

720 miss firing

Welcome Guest, Log in or Register
Author 
John W.

04-05-2002 17:31:46




Report to Moderator

Hi guys, I have a 720 gas and i was disking my feild. Tractor ran fine for a couple hours, But then started to miss fire only under load. If I pull the clutch or lift the disk out of the ground it runs fine I put new points, condenser and plugs. Any suggestions! Thanks




[Log in to Reply]   [No Email]
DON

04-06-2002 12:31:15




Report to Moderator
 Re: 720 miss firing in reply to John W. , 04-05-2002 17:31:46  
Sounds like she's running long enough to heat the coil and it's breaking down. I would replace it with a 40000 volt coil. Don



[Log in to Reply]  [No Email]
Brandon

04-06-2002 12:53:28




Report to Moderator
 Re: Re: 720 miss firing in reply to DON, 04-06-2002 12:31:15  
Don wher edo you get a 40,000 volt 6 volt coil? Seems like a coil wuth taht much output would burn the points up in no time.



[Log in to Reply]  [No Email]
Ron

04-06-2002 10:46:09




Report to Moderator
 Re: 720 miss firing in reply to John W. , 04-05-2002 17:31:46  
Could be that there is moisture showing up in the Distributor cap....as the engine gets to operating temp, moisture is displaced to the cooler parts...the distributor would be one of the last to warm up....Just a thought..... A tree leaf can even blow under a sparkplug cover, and intermittently short a plug... A few drops of water in the carb can cause this, also...



[Log in to Reply]  [No Email]
John W.

04-06-2002 04:55:40




Report to Moderator
 Re: 720 miss firing in reply to John W. , 04-05-2002 17:31:46  
Thanks, I'll check those out. I'm going back to the feild this morning. I'll let you guys know how it went.



[Log in to Reply]  [No Email]
Clooney

04-06-2002 05:04:40




Report to Moderator
 Re: Re: 720 miss firing in reply to John W. , 04-06-2002 04:55:40  
John, make sure the tank vent isn't plugged, or try running with the gas cap loose. Mud dodders like to nest in the tank vent & plug it off. It takes a while for a plugged tank vent to slow the fuel flow.



[Log in to Reply]  [No Email]
mike

04-06-2002 04:00:53




Report to Moderator
 Re: 720 miss firing in reply to John W. , 04-05-2002 17:31:46  
I have ran into a few problems with the automatic
fuel shutoff valves if your tractor has one. I have had the rubber washer on the plunger that
you can see in the fuel bowl stick to the top of the housing and not ride down with the plunger ,causing a slow gas flow.Just visually check it with engine running or push the plunger from top and see if it drops with the plunger. Also when rebuilding these units I have found that the passages are small and have found fuzz-
or corn silk or something packed in around spring
in a few of them partial restricking them. So when checking for fuel flow try to catch it in something to see if stream has good flow or starts out good than slows down. I would guess that a 720 gas at full load needs lots !!

[Log in to Reply]  [No Email]
John T

04-05-2002 19:54:31




Report to Moderator
 Re: 720 miss firing in reply to John W. , 04-05-2002 17:31:46  
John W. Well you have already done my first suggestion (if electrical problem) in new points plugs and condensor, so are the wires in top shape (run her in dark and look for sparks near wires) and are there any cracks or carbon paths in the distributor cap??? A defective coil or condensor can show up after heat builds up also like when the tractor is worked hard. Assuming its not a lack of fuel problem (do you have good flow out the sediment bowl of clean water free gas??) the next heat related suspects after points and plugs and cap and wires are again a coil or condensor, so considering the cost, you might try a new condensor before you look at a heat related coil problem. When you remove the plugs, are they clean and gray looking or black and sooty or black shiny wet looking????? Let us know that and we may be more able to help. Have you tried Autolite 388 plugs??? If the electrical is all in good shape and it misses only under a full load, have you opened the power jet in the bottom center of carb bowl a tad more and tried her???? Ol John T

[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