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MG Midget and Sprite Technical - Fuel Pump Blowing Air, NOT Fuel ?

Once again, then, I have come to beg for a lifesaving dose of expert advice.
Underbody - overhauled.
Suspension - overhauled.
Body - overhauled.
Fresh re-spray - check.
Carbs - overhauled.
etc, etc, etc.

Now, after this very steep learning curve, I have been stopped by a fuel pump?!

1) So it's blowing air through fine (sort of pulsing it through), but no fuel (despite a fresh tank of the stuff). Any ideas?

2) Also, I was wondering if, due to its design, the midget's fuel tank was only to able to deliver fuel if it was over half full (?) because the pick up pipe is located half way up the side of it...

Thanks!

Josh
Josh 'Midget Mad' Spooner

Could be sucking air in through a fault on the pipe between tank and pump. Either splits or bad connections to the rubber hose, or a badly seated connector at the tank itself.
Guy

I'm with Guy on this.

I had a similar problem on my MGB and it turned out that the metal pipe from the tank to the pump had a pinhole in it, right at the top where it curves over the axle.
Dave O'Neill 2

Have you tried sucking fuel from the tank through the pump by taking the pipe off the carb(s) and sucking on it, to prime the pump?

Don't get a mouthful of fuel though, not pleasant.
JB Anderson

As above,

it needs primed

had the same problems with a fuel pump and more recently a washer pump
PeterJMoore

Josh - As stated above, an air leak in the line from the tank to the pump. You could also have a hole in the pickup tube inside the tank (not a common failure, but does happen from time to time). You could also have an air leak in the pump or a fractured reed valve in the pump or a hole in the diaphragm (again, holes in the diaphragm are not real common, but can happen). If the problem is not a fractured reed valve, you should be able to get the pump to start delivering fuel by slightly pressurizing the fuel tank - I have even done that by getting a seal around the filler tube and my mouth and blowing into the tank while the pump is running. If the pump is unable to pull fuel from the tank, even when the pump is dry, then you do have a problem in one of the areas above and even if you can get the fuel flow started, you should follow up o find where the problem exists and repair it so you won't be faced with it again. Cheers - Dave
David DuBois

I agree - the fuel pump is dry and won't pump until it has some fuel in it. Unless something weird has happened to your tank, the fuel pick up will be right at the bottom, and you should be able to pull fuel through with only a half a gallon in it. One way or another you need to introduce some fuel into the pump, then I think it will be away.
Mike Howlett

This thread was discussed on 30/01/2011

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.