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AC-7040 - No throttle response
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dualquads View Drop Down
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Joined: 12 Dec 2010
Location: Ill Annoy
Points: 53 		Post Options Post Options   Thanks (0) Thanks(0)   Quote dualquads Quote  Post ReplyReply Direct Link To This Post Topic: AC-7040 - No throttle response
    Posted: 06 Nov 2025 at 8:24am
Needing some advice..  Think I may have an injection pump problem?  Tractor will start and idle at ~1000 rpm.  Constant or extremely slow throttle, might get 1300 rpm sometimes.  Engine sounds normal firing all 6 but no power, lifting the wings on a bat-wing mower will lug or stop the engine.  I have replaced the fuel filter, rebuilt the primer and blown out the fuel line back to the tank.  The throttle moves the pump linkage fore and aft to the stops on the pump.  Tractor sat in shed without being started for almost 5 months this spring/summer due to my medical issues, was running fine before. 
Thank you for any insight!
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injpumpEd View Drop Down
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Joined: 13 Sep 2009
Location: Walnut IL
Points: 5133 		Post Options Post Options   Thanks (0) Thanks(0)   Quote injpumpEd Quote  Post ReplyReply Direct Link To This Post Posted: 06 Nov 2025 at 8:35am
Metering valve in pump is probably sticking. Take top cover off and timing window off side to drain fuel down, and spray brakleen around the metering valve. If it's sticking, it will not respond to any loads. It may be due for proper servicing if it's really nasty inside. When they get gummed up, they can have the transfer pump regulating piston also stick, causing the pressure to spike and it results in a seized head and rotor assembly. Then becomes a very expensive repair lol!
210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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Clay View Drop Down
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Joined: 11 Sep 2009
Location: Udall, Kansas
Points: 10091 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Clay Quote  Post ReplyReply Direct Link To This Post Posted: 06 Nov 2025 at 9:35pm
Not saying this will work in your injector pump but I dumped some ATF into my John Deere 4050 fuel tank.  This seemed  to help free things up.  Tractor runs perfectly again.
Worked well with my 1983 F-250 with 6.9 diesel.
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GM Guy View Drop Down
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Joined: 31 Jul 2012
Location: NW KS / S.C. ID
Points: 1986 		Post Options Post Options   Thanks (0) Thanks(0)   Quote GM Guy Quote  Post ReplyReply Direct Link To This Post Posted: 2 hours 18 minutes ago at 2:47pm
like Ed said, sticking metering valve.

It seems the 7K series is extremely prone to this because of the belly mounted fuel tanks with large exposed surface area causing wild expansion and contraction due to temps. it seems the  heavy "breathing" is more prone to pulling in condensation and therefore water in fuel, and that causes rust and corrosion. I generally keep my 7K series full of fuel with a good lubrication boosting additive like Stanadyne Lubricity formula.

Whenever I have one stick I blow out the upper housing and refill with that additive, then get my fingernail down there to gently work the tab on the valve, usually you can feel it break through a varnish layer then work freely if it hasnt been sitting long.


Edited by GM Guy - 2 hours 16 minutes ago at 2:49pm
Gleaner: the properly engineered and built combine.

If you need parts for your Gleaner, we are parting out A's through L2's, so we may be able to help.
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Joined: 12 Sep 2009
Points: 22250 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DrAllis Quote  Post ReplyReply Direct Link To This Post Posted: 2 hours 4 minutes ago at 3:01pm
I believe that was one reason they eventually went to the plastic tanks. Less sweating.
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