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Thread: Fuel pump hookup

  1. #1

    Fuel pump hookup

    Have the old style fuel pump for F134 motor ( no glass bowl ). The inlet port is clearly identified. However there are two other ports. Anyone know which one the outlet would be? Also I assume I'd plug the remaining port. Thanks

  2. #2
    Senior Member
    Join Date
    Nov 2019
    I don't know, some of the others probably know but I think some fuel pumps were used to supply vacuum.

  3. #3
    Super Moderator LarrBeard's Avatar
    Join Date
    Nov 2014
    Ft. Wayne, IN
    There should be four ports; two for fuel and two for vacuum. The fuel ports are on top.

    FYI, a split diaphragm in a fuel pump will dump raw gas into the crankcase - more bad JuJu (that's twice I've said that tonight...)

    The two bottom ports are a vacuum boost pump to try to help the vacuum wipers when you open the throttle and manifold vacuum goes to atmosphere instead of 15-inches of suck. (A technical measurement term, not an opinion of anything).

    But, having said that - vacuum wipers even with a boost pump - suck. If I had any intention of driving the '48 in any kind of precipitation, I would put one of the 6-volt electric wiper motors on. Like side mirrors, it's a survival issue. I'm very seriously considering LED headlights. The stock 6-volt lights look and shine like kerosene lamps. (Early autos had acetylene lamps - those are BRIGHT!)

  4. #4
    No vacuum ports on this one. One orifice that clearly says "IN" and two unidentified. One facing left and one facing right. This unit fits precisely on the mount; so I'm assuming it will work. I got it on EBay. Pumpfuel.jpg

  5. #5
    Super Moderator bmorgil's Avatar
    Join Date
    Dec 2018
    Northwestern Ohio
    I don't recognize that pump, but it isn't the original style that's for sure. I would say it is a "one size fits all" in which case it has two outlets to make it more universal. It looks like a more modern AC type pump upside down. You probably plug one. Have some one crank the motor. You should feel a little puff of air on the outlet or outlets and vacuum on the in.

    Depending on what the pump is, one port could be the overflow. On some pumps in particular Marine applications, if the diaphragm fails fuel flows through the overflow into the carburetor to flood the engine and stall it. This is preferred to the fuel being pumped into the crankcase where it will explode. On some pollution controlled vehicles the port directed the flow back into the fuel tank.
    Last edited by bmorgil; 02-25-2020 at 07:12 AM.

  6. #6
    Super Moderator gmwillys's Avatar
    Join Date
    Aug 2017
    Just make sure you have the spacer plate behind the new fuel pump. Everything would bolt together, but the follower will be too deep past the cam. It will pump fuel, but at a slower rate if any at all.

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