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Starting Cummins M11 after sitting

Welder Dave · 2026-05-28 23:14

I'm getting everything ready to move the Cat and dump truck to the new property. The dump truck hasn't been started since last summer. I thought I fixed the loss of prime issue using a shorter fuel filter. The last time I went to start it the batteries were a little low. I cranked it a bit but it wasn't turning fast enough so I just left it. I only mention this because when I went to start it today I cranked it about 5 times for about 10 seconds and it didn't fire. I'm wondering if the slow crank when it didn't start sucked some fuel out of the filter? I figured the problem was fuel so I took the filter off and fuel was down about 1 1/4". The oil level was right at the full mark. I filled the filter full and after two attempts it started up and ran great. I'm wondering if it's somewhat common to loose prime after sitting for almost a year? Also wondering if it helps to give it more throttle when trying to start it after sitting for long periods?

Replies9
  1. #1Truck Shop2026-05-29 07:50

    And that's not uncommon for that period of time.

  2. #2Deere500a2026-05-29 09:38

    Hand pump prime from there pump til feel pressure.

  3. #3Welder Dave2026-05-29 14:00

    No hand primer. It originally had I think a Racor filter with a push button but I took it off. The shop I took the truck too to check over even put a new filter on it. Whoever did it must have been blind because it wasn't even hooked up! The fuel line made a loop from one side to the other. On advice from TS I removed it. Apparently they are known for air leaks. Glad to know it's not uncommon.

  4. #4BC Placer gold2026-05-29 17:30

    We have a similar situation with our L10 powered dump….I know it needs all fuel lines replaced but have not got around to it yet.

  5. #5Welder Dave2026-05-29 23:00

    I replaced the fuel line from the cooling plate to the filter. No noticeable leaks but it attracted dust so I figured it could be weeping. The short filter really was a game changer. If I have to top up the filter after the truck sits for month's I'm OK with that. They're calling for heavy rain in the next few days but once that's over I'll see how the truck starts.

  6. #6mekanik2026-05-30 09:54

    If I remember there was a fitting in the cooling plate that had a check valve in it. They were easy to disassemble and clean.

  7. #7Welder Dave2026-05-30 15:47

    I did check and clean the check valve. Made no difference with the loss of prime issue but the short filter did. I'll see how it starts the next time I go out.

  8. #8mekanik2026-05-30 16:41

    The shutdown solenoid on the fuel pump has two sealing discs in it if I remember correctly when they get old they can let the fuel drain back as well.

  9. #9cfherrman2026-05-31 14:30

    I plumed a prime port on my fuel line right by the take buy putting a tee in and some valves. A clicky clacky works till it hits pressure but I was using a super duty fuel pump that will pump past the spring. My fuel tank is from 1954 and has problems so I put in a fass lift pump for a 6.4 diesel and that has fixed a ton of problems with the tank. I hope to be finally replacing the tank in the next coming weeks.