[Mgs] MGA FUEL PUMP [now MGB]

[Max Heim]

Before I ran this test, I replaced the fuel filter (at the carbs), and
inspected the screen in the pump (which was clean).

Aaron asked about the gas cap -- since I have had the same gas cap for over
20 years, I really don't suspect it. But I may run the check just the same.

Don asked about the contact points. No, I have not inspected them yet -- the
first step was to establish that the pump was indeed the problem. But I
would be a little surprised if this were a problem on a 3-year-old pump
(well, I suppose it may have been sitting in stock for years before that).
Again, I will have to look -- I will check this while investigating Barney's
suggestion.

Thanks to all for their suggestions.


Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires



on 1/10/10 6:21 PM, Ron Fine at RonFineEsq at earthlink.net wrote:

> Sounds like maybe there is dirt in the pickup in tube from the gas tank to
> the pump.  Maybe a clogged filter in the pump.  It starts pumping until the
> dirt gets so thick that nothing can get through.  When it rests, the dirt
> falls away.
> 
> Ron
> 
> 
> ----- Original Message -----
> From: "Max Heim" <max_heim at sbcglobal.net>
> To: "MG List" <mgs at autox.team.net>
> Sent: Sunday, January 10, 2010 4:12 PM
> Subject: Re: [Mgs] MGA FUEL PUMP [now MGB]
> 
> 
>> My MGB has been suffering from what seems to be fuel delivery problems, so
>> I
>> just attempted this test. I attached a length of spare hose to the exit of
>> the fuel filter and ran it onto an open container (a measuring cup from
>> the
>> kitchen). It was only a US pint container, so I didn't expect to be able
>> to
>> run for a full minute.
>> 
>> When switched on, it started off fast, filling about 2/3 cup in less than
>> 15
>> seconds. But then it stopped all by itself, so I switched off after 30
>> seconds.
>> 
>> If this is what it has been doing in operation, it would completely
>> explain
>> the symptoms. After driving at freeway or expressway speed for a few
>> miles,
>> the engine would sputter and lose power. After pulling over, I would hear
>> the fuel pump kick back in, and after a minute, I could accelerate away
>> smartly. In city traffic, it never had a problem, presumably because
>> sitting
>> at idle at traffic lights would give the pump a chance to catch up.
>> 
>> This is a replacement SU pump from Moss that I only installed in late
>> 2006.
>> Its predecessor failed in a similar manner, but only after at least 25 and
>> possibly 40 years.
>> 
>> --
>> 
>> Max Heim
>> '66 MGB GHN3L76149
>> If you're near Mountain View, CA,
>> it's the primer red one with chrome wires