Fuel Pump Problem
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Thread: Fuel Pump Problem

  1. #1
    Join Date
    Dec 2018
    Pittsville WI, USA

    Default Fuel Pump Problem

    Greetings, I am restoring a 61 Jolly for a client and I am having trouble with the fuel pump not pumping. The owner of the car sent it out to a company to rebuild it and I installed it into the car and it still won't pump. I connected a vacuum gauge to it and the needle just bounces, does not create a vacuum. I took a hand vacuum pump and connected it to the hose at the carburetor and sucked fuel from the tank all the way up so the lines, filter and pump have fuel in them and there is still no fuel. It is my understanding that the engine is the same as the 4CV and Dauphin so has anyone have an idea of what is wrong?

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  2. #2
    1000+ Posts renault8&10's Avatar
    Join Date
    Mar 2002


    Most rear renaults have their fuel pump driven off a lever off the cam. New fuel pumps should be available from European suppliers like frandoze.de

    I would’ve recommended Jacques rear engined renaults in California, but I believe he has recently closed down. I would source a new fuel pump and try that. Even a secondhand one. They are normally pretty reliable.

  3. #3
    1000+ Posts
    Join Date
    Nov 2010


    By Golly a Jolly
    I seem to remember those pumps as easy dissembled and simple ? Sounds like one of the valves, perhaps the outlet is installed the wrong way up, or the valve is stuck or held open.

  4. #4
    Too many posts! JohnW's Avatar
    Join Date
    Jul 2001
    Perth, WA, Australia


    Yes, they are pretty reliable pumps. They just have a diaphragm operated off a cam and, in the top of the pump (held on with 8 screws or something like that) there are two little disc valves with springs).
    Great to see another Jolly being restored in USA! Are you connected to ROCNA, the Renault Owners Club of North America? They are pretty active.

    I agree with KB. Just buy a new one. They are also available from Bretagne Auto Retro, probably Melun Retro Passion too. I'd email Jacques too just in case you strike lucky!

    We get good and fast delivery from Europe. Postage is expensive, so we try and buy several things at once to spread the cost. Does it need shock absorbers for example? New ones are available, as are all the suspension bushes.

    You can get them with and without a manual priming lever, and I'd strongly recommend the latter, "avec levier", then you can hand-pump up fuel when the car has been sitting for a while rather than using the starter motor to crank and crank. I can't remember the last time I had one of these pumps fail.

    Some of our local owners have fitted 6V electric fuel pumps too, even running them through the body of the old pump so it looks authentic.

    Regarding the one that is misbehaving, if you pull it off the block and operate it by hand with a hose into a jar with fuel in it, or just suck and blow on the inlet and outlet you'll soon know whether the valves are working.

    Good luck and please post more photos as the restoration comes along. We're all out here to help.


    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

  5. #5
    VIP Sponsor 59 Floride's Avatar
    Join Date
    Oct 2010
    It's how I roll...Brisbane


    Jolly good show. There is the possibility that the upper body of the fuel pump has been put in the wrong way around and therefor the inlet is on the wrong side. Try removing the 8 or so screws out of the body and rotate it 180 degrees.

  6. #6
    1000+ Posts Fordman's Avatar
    Join Date
    May 2004
    Perth/West Australia


    As said above, these old fuel pumps are easy to repair.
    Common assembly fault is to put both valves in same way up. One should go upside down. Sometimes they fall out if not secured with a screw, and need a little bit of burring over with a centre punch on the body to hold the valve in securely.

    With pump apart, test the valves by blowing/sucking on the inlet and outlet pipes. Inlet from tank, you should be able to blow into the pipe but not suck back. Outlet to carby, you should be able to suck but not blow. The valves usually make a noise like a duck when doing this. Good fun, eh?

    About the only other thing to go wrong, is the diaphragm is split or leaking. On assembly, the trick is to loosely tighten the 8 screws, so the diaphragm is not clamped tight, then with the body held in a vice, depress the lever that runs on the camshaft which pulls the diaphragm down, and tighten the 8 screws while holding the lever hard "on". This prevents the diaphragm stretching during operation, and will extend its life.

    Final test, vacuum gauge on inlet pipe should hold for a few seconds when lever pumped. On outlet side gauge should hold pressure, maybe about 4-5 psi.

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