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MG Midget and Sprite Technical - fuel filter/pump question

72 midget, 5 spd

Now (having replaced upper fuel line and
accelerator cable!) she seems to start and run
like she used to (whew!).

But I noticed that the upper fuel filter (small
plastic, mounted horizontally off the front
SU carb) has fuel only in the bottom of the
filter body, and not very deep either. So most of
the filter body appears empty.

Is this normal? I just don't remember what it's
supposed to look like. Or could the pump be
shot??

chuck NC USA
chuckc

it is on my '73

they didn't have fuel filters there originally (well not on UK cars anyway)
Nigel Atkins

it is normal for the filter to be only partially filled, don't worry about it


Norm
Norm Kerr

why I am concerned is ...

t'other day went out, turned the key, it started,
hit the gas, went right to the floor..broken cable.

replaced the cable (bike shift cable). started it up,
heard a funny noise, opened hood (AGAIN!) and found
the upper fuel line pissing gas.

Replaced the upper hose with whatever I had (which
turned out to be a vacuum hose). Drove off. Got
less than a mile and the engine died. Towed it home.

Have now replaced the vacuum hose with real fuel hose.

Starts and idles ok, runs in the driveway ok.

Just do not trust it. Filter is almost mt while
engine runs. Will I get just down the street again?
Should the filter be almost mt? Maybe the pump
is shot??

Soon will drive down the street with my wife and a
towing chain following and we will see.
chuckc

I am not sure why you think your fuel pump's health is related to a broken throttle cable and a broken fuel hose.

Is this a car that you've owned very long, or one that you've just bought and are becoming worried based on already having two things fail within the first few miles of ownership?

In either case, a failed fuel line makes me think that the rubber had dried / aged, which leads me to start worrying about all of the other rubber parts on a car that was just bought / history unknown.

Rather than the fuel pump, the other parts that I would check are the fan belt, radiator hoses, rubber fuel hose near the pump and rubber brake lines. Flex each and look closely if any of them show signs of cracking too.

Other things to check with a newly purchased car are: engine compression test, rear brake adjustment, brake, clutch and coolant fluid color & condition, oil and filter change, suspension check for worn/loose joints. Stuff like that.

You can also test the fuel pump's health. Here is a link to a website with several articles on SU fuel pumps, including simple tests to confirm one:

http://homepages.donobi.net/sufuelpumps/sufuelpumparticles.html

Norm
Norm Kerr

It's a 72 Midget we have had for over 15 years.
We did the Rivergate 5 speed, cam, and 1.5 rollers.

What happened is: got a fuel line leak. Replaced the
leaky fuel hose with vacuum hose (temporary!!). Drove
less than a mile and it died. Towed home. Replaced
vacuum hose with reinforced fuel hose. Seems OK??

But now the fuel filter fills only 1/3 or less.

Question: When it died with vacuum hose as fuel line,
was it the fault of the vacuum hose or something else
(like the fuel pump).

And if the latter, is whatever caused the problem
causing the low level in the fuel filter??
chuckc

why not just get rid of the non-standard filter. If you have a standard SU fuel pump there's a filter in that, no other filter is needed.
David Smith

This thread was discussed between 14/02/2011 and 16/02/2011

MG Midget and Sprite Technical index

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