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  1. #1
    New Member
    Join Date
    Nov 2011
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    5
    Tractor
    McCormick

    Default McCormick loses power as you run it

    Hello folks,
    My neighbor has a McCormick (50-60 hp) we've been trying to repair. Dealer said it was injector pump and had it rebuilt - did not fix. Problem: as you run the tractor under load, approx. 10-15 min. into job, it starts acting as if it's grasping for power and struggling to keep up the rpm's (like water or air in fuel). If you stay on the load (cutting moderately heavy hay), it will eventually choke itself off. Seems obvious to be fuel related. Other things done already: Tank drained and new fuel, injectors bled. If you wait 30 minutes, tractor will start back and resume work until it eventually happens again. You can hear the fuel pump kick on when key is activated, but it sounds "bubbly", like it's sucking air into the system. I really think air is getting into the fuel system, but I just don't know where. Any leads?

  2. #2
    Super Member
    Join Date
    Feb 2006
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    8,076
    Location
    VA
    Tractor
    JD2010, Kubota3450,2550, Mahindra 7520 w FEL w Skid Steer QC w/Tilt Tatch, & BH, BX1500

    Default Re: McCormick loses power as you run it

    Fuel filter? Pleated filters can collapse slowly under suction. This reduces their area and worsens til engine starves. When you let it sit the filter opens back up ... repeat.
    larry
    This side of 40
    JD2010, Kubota L3450/FEL w SK QC, L2550 w FEL
    Mahindra 7520 [Pinky] /FEL w Skid Steer QC/w Tilt Tatch & BH, BX1500 [Mighty Mouse]
    IH37 Baler, CCM165 Drum Mower, JD Rake
    JD 127 bushog, Flail, SK Tilt Tatch , KK tiller, Rhino rear blade, Post driver, post auger, chipper, pallet fork, Grapple/Loader Buddy, Homemade Splitter/DC Welder

  3. #3
    Platinum Member
    Join Date
    Apr 2011
    Posts
    736
    Tractor
    cx70,5510,4630,5005

    Default Re: McCormick loses power as you run it

    i would blow the line out between the filter and tank.then change the filters.some mccormicks have a little filter before the lift pump.

  4. #4
    Platinum Member
    Join Date
    Dec 2005
    Posts
    661
    Location
    Central Maine

    Default Re: McCormick loses power as you run it

    It does sound like a filter problem.

  5. #5
    New Member
    Join Date
    Nov 2011
    Posts
    5
    Tractor
    McCormick

    Default Re: McCormick loses power as you run it

    Well, we replaced the filter yesterday. The old filter did not look as if it had collapsed from suction. Everything looked pretty normal. Bled air at the injectors, then at the pump, then at the injectors again. Tractor performed as it ever has. The longer it runs, the more it seems to starve for fuel. However, while bleeding injector #1 (the one closest to the pump), when I cracked the nut, it did not seem as if it affected the function of the machine like the other two. Almost like that cylinder was not working anyway. We are going to pull that injector today and look at it. Thanks for the replies folks...please keep them coming!!

  6. #6
    Gold Member
    Join Date
    Aug 2009
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    468
    Location
    Adelaide South Australia
    Tractor
    Foton FT404, International 444 with forklift, International B250, Kubota L2000DT, Truck converted to all terrain forklift and lots of other junk

    Default Re: McCormick loses power as you run it

    Hi
    Is there a filter/screen actually inside the fuel tank. Does it have a tap on the outlet from the fuel tank.
    I had an old International that got a tiny tiny pebble lodged in the fuel tap.
    When it was stationary and I checked the flow through the tap it was fine....After 10 or 15 mins use the power would slowly diminish.
    Cleaned the tank, filters etc etc could not find the fault.
    Finally found it when the pebble got lodged hard in the tap and cut the fuel off completely.

    Just a suggestion.

  7. #7
    Elite Member
    Join Date
    Jul 2006
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    4,409
    Location
    Northwest, WA

    Default Re: McCormick loses power as you run it

    A slight positive pressure on the tank might show a small draw side leak.

  8. #8
    Gold Member rdbigfarmboy's Avatar
    Join Date
    Jan 2005
    Posts
    392
    Location
    Collinwood, TN
    Tractor
    1

    Default Re: McCormick loses power as you run it

    Its an obstruction in the tank bottom or in one of the lines. When the fuel in the bowl or filter is used up it cant draw enough to keep running.
    Remove the tanks flush shake dump. incredibly common on tractors that sit a lot or get fuel poured from can or jugs. remember a small piece of plastic or foil is all it takes....

  9. #9
    Gold Member the6shooter's Avatar
    Join Date
    Dec 2006
    Posts
    455
    Location
    oklahoma
    Tractor
    MF 1643

    Default Re: McCormick loses power as you run it

    hi guy's
    One thing not discused here, is the fuel cap vent clogged ? you may want to check that 1st. before pulling the fuel tank. just my
    david

  10. #10
    New Member
    Join Date
    Nov 2011
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    5
    Tractor
    McCormick

    Default Re: McCormick loses power as you run it

    Pulled the #1 injector and it tested O.K. In the A.M. my neighbor is draining the tank and blowing out the lines. I thought he did this already, but apparently he just drained the fuel and replaced it with new. A clog sounds as good as any other right now. Hopefully this will do it----I'll keep ya'll posted. We had checked the fuel cap...o.k. there. One thing, this tractor did sit a few years at the dealership as a trade in. Good call rdbigfarmboy, we shall see....

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