Mk 10 fuel pump

Just fitted a new pump , it runs fine , but no fuel . Plenty in the tank , does it need priming ?

My standard SU required priming once, I imagine the valves seal better when wet and it was airlocked. Does it tick fast, or slow?

Is it the “in tank” early version, or the later ones mounted high in the boot ?

afaic, the high mount one hasnt needed priming on the couple of occassions I have had it out

Where is your fuel filter ? the engine bay ?..I would check whats going on there

maybe a brand new one has a sticky valve, or airlock

In the past, with other pumps, I have pre-tested them prior to install with fuel from a 5 litre container pumped into a bucket

It’s suck time ! :wink:
(20 char.)

It’s the one high up in the boot in an inaccessible position , and it’s ticking fast . Filter is common to both pumps , I think , and the other pump delivers fuel fine . I tested it’s performance with a battery :battery: prior to installation , but , yes , testing it with fuel would have been a good idea . It’s practically impossible to get your laughing gear round that pipe where it is Piotr .

Okay Kenny, I assume (don’t know!) that it works like the usual SU pump, ticking fast means no fuel or an air leak into the suction like.

Maybe the line from the tank is clogged or otherwise dry
Maybe the line is leaking, internally or externally.
Maybe the pump is defective.

You can try to pressurize the tank slightly while the line to the carb is disconnected. Try it with the pump on and it may just need a little liquid to get going.

Try not to pressurize the outlet sides of either pumps if they have little plastic valves, that may tear them.

Ok David , away tomorrow , but back on Thursday , will do some testing , thanks :+1:

If you have the original submersible pump in there, there can be a few issues.

The nylon fuel line, which I believe is no longer available, can become old and brittle.

There is a fine mesh pick up screen that sits at the very bottom of the tank. It can get clogged.

Inside the pump is a large metal ball that acts as a check valve so one tank does not fill the other. Sometimes, they can stick.

If your pump is still in there, I suggest removing the impeller. They can come apart and block the flow.


I believe the original fuel line is available, at least someone I know of got some a few years ago

I must say my original lines are good, that stuff sure does last well !

I would suggest to the OP that he bites the bullet and removes the pump to do a fuel test, as that will both prove whether its working at all, but also prime it for re-installation

I took mine out recently as it wasnt working…loose screw from the last time I had it out maybe 20 years ago

I assume the fuel trapped inside the pump eases the priming, even though fuel will run out when you remove it

So if has an impeller and doesn’t click at all, in that case I would still try to get it wet, even more so actually. If that doesn’t work it has to come out and be inspected on the bench.

I had to pull my submersible out a couple years ago. It no longer works. The SU pump in the boot went bad and I had to rebuild it. I could not get fuel flow. Old gas plugged up the intake screen and inside the submersible. The nylon line inside the tank was brittle and broke on me. When I ordered replacement, I was told the original inside diameter was no longer made and the replacement had a bigger ID. I think it was metric. The only way I was able to get it to seal was to get it good and hot with a heat gun and then twisted wire around it to clamp it down until it cooled.