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  1. #1
    Senior Member turftech 1's Avatar
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    Polaris fuel pump question

    Hi all,
    the kids were riding the Mrs' Polaris 325 magnum, it ran out of fuel, so I went out, filled it up....won't start. Pulled the air filter,sprayed some carb cleaner into the air intake and it will fire up for a second, then die. Fuel is on, fuel filter is clean, gas is flowing into the fuel pump, but not out. To be honest, I am not sure how the fuel pump works, it has no electrical connections, just has one hose going in, and 2 coming out. I unhooked the two out hoses and cranked it over a bit, nothing comes out. I'm thinking one hose perhaps drives the pump using crank case vacuum or pressure.... not sure. Here's a pic, any ideas on what hose does what? Or why it's not working?

    fuel pump.jpg

  2. #2
    Hangin with Neck and GTO The Restore Kid's Avatar
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    HUH... yeah thats how they work.. That vacuum hose pumps a little diaphragm in there... I don't know why it wont work if ya have fuel to it.. Maybe it somehow flip flopped a diaphragm some how when it ran dry... Try taking that hose off and blowing in it then sucking on it as hard as ya can and see if it you can get it primed again.. Or even like a bicycle pump and try back and forth pressure.. I don't think I'd go putting no 60 PSI into it but just something to try fluttering that diaphragm..

  3. #3
    Hangin with Neck and GTO The Restore Kid's Avatar
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    OH hey.. maybe try filling the out side of the fuel line too... and put it back on THEN start the motor so it can run for a while and get shit happening again.. That would be MY first move I think.. Pull the line at the carb and back fill it to the max and stick it back on..

  4. #4
    Senior Member turftech 1's Avatar
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    Good to know, I will try that. Perhaps I'll try just bypassing the pump, see if it runs at all. I wonder if I could just replace the diaphragm. A "new" (used) pump is $20 + $12 shipping.

  5. #5
    Hangin with Neck and GTO The Restore Kid's Avatar
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    Theres probably nothing TOO aweful major wrong with it.. They gum up from sitting for 60 years but otherwise I'd say it should work... I'd try taking the line off at the carb... Hold it up so you can fill it allllll the way to the tippy... Then pinch it off so ya can ram it back on the carb... Fill the carb first and everything.. Maybe one smaaalll bubble 1/3 the size of a pencil eraser when the whole project is finished... THEN fire it up and run the hell out of it.. If it dies again THEN I'd say go deeper..

  6. #6
    Senior Member turftech 1's Avatar
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    Well, I just bypassed it, plugged the fuel filter straight into the fuel line going to the carb, fired right up and runs like a monster. The line from the crankcase is puffing, so I think the diaphragm is either torn or gummed up.

    Stupid question maybe, but can I just leave the pump bypassed? Will it hurt anything?

  7. #7
    Hangin with Neck and GTO The Restore Kid's Avatar
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    If it gets plenty of fuel to run right and it can gravity feed until the tank is empty... I don't see how it could..

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