Fuel pump

[mogieminor]

Replaced points in fuel pump and works perfectly OK on bench. Tired it several times over 24 hour period works every time.
Put on car and it pumps for about 5 seconds and stops.
Took of car, screwed diaphragm in 1 hole pitch reasembled, works on bench but only 5 seconds on car again.
Should I be screwing diaphragm in or out to get it to work constantly or should I be looking elsewhere??
Any advice would be much appreciated

[Edward1949]

Assuming you've plumbed-in the petrol feed, it's supposed to stop clicking anyway once the float chamber is full.

[mogieminor]

Hi
Thanks for response
It stops clicking before float chamber is full. When removed from car there is small amount of fuel in the pump but not in the inlet or outlet pipes

[jagnut66]

Hi,
When I replaced the diaphragm on mine with a E10 resistant one from the States I found that if I screwed it in too tight it didn't work, so it sounds like you need to slacken it off a little.
Best wishes,
Mike.

[les]

There’s a guy on U tube showing the diaphragm adjustment, I tried to post a link but it wasn’t having it. Google — su fuel pump instructions, and look for Tony Hillyards video. The diaphragm assembly is about 10 minutes in.

[mogieminor]

Many thanks for the info. I tkink I’ve already seen those but will look again with perhaps a bit more concentration.
I’ve followed standard procedure which hasn’t worked yet but some say it’s very difficult to get right. Looks to me it’s very very very difficult to get right but I’m sure we’ll get there in the end

[mobylette]

Here is a link to the video mentioned:

https://m.youtube.com/watch?v=oU5uLjuOQdM

[jaekl]

The book says to unscrew 2/3 turn from point the points just throw over. I fine a full turn is more reliable running operation. This slack ensures that the diaphragm can move enough to ensure that the points open. We can't check if the points can close again before it hits the middle plate. That could be a problem if the diaphragm is too loose. When mounted in the car, the vacuum of the fuel line puts the diaphragm in a different environment. That's why it performs differently on the bench. Cover the inlet with your fingers to give it a different test. Same with the outlet.

[mogieminor]

Hi all
Firstly thanks to you all for the advice offered. Looks like problem is solved as it now fires up OK. Road test will have to wait in this weather.
General opinion including utube clips seemed to indicate that diaphragm needed to be unscrewed more but in fact eventually I screwed it in a full turn from theoretical ideal position but having said that i did not find it easy to establish point of click over as it seemed to vary.
Once again many thanks to contributors

[les]

Hope it’s ok now. You are right, the throw over can seem to feel a bit hit and miss, and if so can lead to the need to vary the diaphragm position once or twice.

[mogieminor]

It’s fine thanks Les. Stared it up a few times this afternoon and let it run for a bit all without problems.