Farm Equipment - Allis Chalmers 7040 fuel issues

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Allis Chalmers 7040 fuel issues

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=123669
Printed Date: 27 Sep 2024 at 9:28am
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Topic: Allis Chalmers 7040 fuel issues

Posted By: nick121
Subject: Allis Chalmers 7040 fuel issues
Date Posted: 22 May 2016 at 8:45pm

Hi, My Allis chalmers 7040 has been running fine until yesterday when it stalled out while plowing. It started and I kept going and it stall again but I managed to get it to the barn where it finally quit. I ran out and looked and there was air bubbles in the top of the filter which is see through glass. With the hand primer an another person pumping we can pump enough fuel the tractor will start but it runs rough, If you continue using the hand primer it smooths the engine out. The manual mentions the transfer pump is that part of the injection pump? I cant find an inline pump anywhere. Where do I start should I change the filter or all the lines?

Also I have 2 gleaner f2 combines and the have a inline electric fuel pump wired up by the last guy, Maybe I could add one to my tractor? any help would be great

Replies:

Posted By: Orange Blood
Date Posted: 22 May 2016 at 9:08pm

It sounds like you have an air leak. Look for damp spots on the inlet lines, although they will not always be there, air molecules are smaller than fuel.

The first suspect would be the primer pump, they tend to get hard rubber parts over time, and start leaking. Does it leak like a sieve when you pump it? If so, start by rebuilding it, a cup of coffee bets that is your problem.

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Still in use:
HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060
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Posted By: SHAMELESS
Date Posted: 22 May 2016 at 9:43pm

and change the filter too

Posted By: nick121
Date Posted: 22 May 2016 at 9:48pm

I will be changing the filet, I can hear air or something when I use the primer pump. The injector pump leaks too but I dont know where and Its always done that. I will try running the tractor from a Jerry can to eliminate the line from the fuel tank. If that doesn't work Maybe I can put a bypass line around the primer pump?

Posted By: MACK
Date Posted: 22 May 2016 at 9:56pm

Filter is the most likely place to suck air, especially if has the glass filter. Also put hose clamps on all hoses from tank to filter. Usually there is a restriction some where that causes one to suck air. MACK

Posted By: johnkc
Date Posted: 22 May 2016 at 10:56pm

My 7040's problem was the rubber line from the tank to engine. It did not leak fuel but sucked air.

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I support the development of hybrid automobiles and alternative fuels as I need DIESEL fuel for my ALLIS CHALMERS!

Posted By: nickia
Date Posted: 22 May 2016 at 11:31pm

look under the tractor at the fuel line mine rubbed thru from the plate under the tractor that covers part of the fuel tank sucking air

Posted By: Dave in il
Date Posted: 23 May 2016 at 9:24am

I still carry a primer pump repair kit in my pickup from back when I used 3 7060's and 200 to farm. They don't last forever.

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AGCO My Allis Gleaner Company

Posted By: Mgraber
Date Posted: 09 Oct 2017 at 10:34am

If the filter sucks air why and how do u fix it. I have been fighting my 7045 allis chalmers for a year now. It will start run for about 30 sec and then u see air bubbles in filter and it dies. I then the primer is shot when u push plunger ther is nothing. Changed the o rings on tube that connects to fuel filter. It rand pretty good one day and next day back to not running.

Posted By: nick121
Date Posted: 09 Oct 2017 at 11:10am

hi, I ended up bypassing the primer pump.. Added and electric pump, it isn't wired to run though, just if I need to prime it I can touch the wire to the battery and let the pump do the work. The primer was leaking must have had bad o rings or something.

Posted By: MACK
Date Posted: 09 Oct 2017 at 10:31pm

Replace the glass filter with a spin on filter. If there is a restriction some place it will suck air somewhere, and the filter is the easiest place for it to get air.
Put a vacuum gage in line just before pump. Should not pull more than 4 inches of vacuum, wide open. If it does, there is a restriction some where.
I have never saw a primer pump suck air. MACK