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MG Midget and Sprite Technical - testing a fuel pump

Hi all,
Sorry to trouble you.
( Mk III midget 1275 with previously posted starting problems).
Got a lovely fat spark now ( YAY !) but still wont start. Took off the fuel line at the carb and turned it over - no fuel in the vessel I used to catch it...so i'm guessing its a clapped or stuck fuel pump?
Is there any way of testing an electric fuel pump- there is def new fuel- bought it last weekend and the fuel gauge reads it.
I have checked my Haynes and Motorcraft books and neither tell me how to test an electric pump. ( at least I cant see where ....)
Any ideas please?
cheers
colin
c frowen

When you switch on the ignition switch do you hear a ticking sound?

An operating fuel pump with an open ended fuel line should tick aggressively.

If you can not hear it ticking you then need to check if there is power to the pump. It is located under the rear of the car above the axle and should have a wire entering the top. check this wire for 12 volts when ignition is switched on.
Robert (Bob) Midget Turbo

Colin. There are some good tech articles on the electric SU fuel pumps at: http://homepages.donobi.net/sufuelpumps/ done by David Dubois who rebuilds them as a retirement profession. I am using one of his rebuilds on one of my MGBs with good luck over several years of use.

Les
Les Bengtson

Colin - e-mail me at SUfuelpumps@donobi.net and I can guide you through testing the pump. There are two different models of the SU pumps used on the Midget and if you can send me a picture of the pump on your car, I can tell you if it is better to rebuild a bad pump or purchase a new one. Cheers - Dave
David DuBois

could be between carbs and pump(?)
N Atkins

With ign on, tap the pump body with a piece of 1" x 1/2" piece of wood... this normally encourages the points(*) to work for a little longer (hours, days, weeks, or...); if the pump re-starts on being tapped, it really needs its points cleaning. This is a 10-min job (not counting removing and re-mounting the pump, that is).

A


(*) Points close and solenoid pulls rod against a spring; the other end of the rod is connected to a diaphragm that draws fuel into a chamber; when rod reaches end of movement, the points have disconnected, and the rod returns to orig position under force of the spring; at the same time, the diaphragm pushes the fuel up the line. Over a period, the points (2 of them) become pitted and covered in verdigris.
Anthony Cutler

This thread was discussed between 10/11/2011 and 11/11/2011

MG Midget and Sprite Technical index

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