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  1. 02-23-2018, 02:11 AM #1
    1ranger487vs
    1ranger487vs is online now
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    why do ox66 motors have 3 low pressure fuel pumps

    trying to understand how they work on a vx200 tlrb. why 3 pumps, thx
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  2. Rich Z
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    #2 02-23-2018, 06:09 AM
    Honestly, I dont know why 3. Hpdi runs on 2 but ox66 uses more fuel so the answer maybe 2 wasn't enough to support the fuel demand. They work of engine crankcase vacuum pulses moving a diaphragm back and forth and pump fuel from the boats tank into the vst. Go with electric lift pump and be done forever with thorn diaphragms.
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  3. yam911
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    #3 02-23-2018, 07:47 AM
    My Mercury EFI (similar to the OX66) used only one mechanical lift pump. It worked well. But the pump was in front of the fuel filter.

    For some reason unknown to me, Yamaha likes to use parts. If one part will get the job done, Yamaha may use two. Or three.

    Pumps don't do so well pulling gasoline as they do pushing gasoline. Yamaha pulls gasoline through the primary fuel filter. Maybe they need to use an extra pump or two to get the job done.

    I agree with Rich. Shift to an electric fuel pump in the boat and do away with all three pumps. Your motor will never be starved for gasoline.
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