Moss Motors, Ltd

My car lived its life in S. Dakota until a year ago, wen it moved t Pennsylvania and is on a diet of 10% ethanol in the gas.  Now the pump is leaking at the gasket at the gasket when pressurized.  Is ethanol the culprit, and if so, what's the fix?  Thanks.  Ed Singer, Villanova, PA.

Ed - There are two gaskets at the base of the coil housing.  One is between the diaphragm and the top of the sandwich plate, the other is between the sandwich plate and the actual pump body (there are other gasket under the inlet and out let fittings and under the plug for the filter.  I suspect that the leak is coming from the gasket between the diaphragm and the sandwich plate.  You can determine this by wiping the perimeter of the pump body and sandwich plate clean and dry, then watch where the fuel starts leaking out.  If I am correct, then the problem is most likely an old and deteriorated diaphragm.  This may have been accelerated by the ethanol, but it would have eventually started leaking on fuel that doesn't contain ethanol.  The pump is probably in need of more than just a new gasket (which is, by the way a fiber gasket and pretty much immune to ethanol), it probably should be treated to a complete rebuild.

 

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Cheers,
Dave
http://homepages.donobi.net/sufuelpumps/

You didn't say what kind of car the pump came from.  There a 4 styles that I am familiar with made by SU over the  years and I am rebuilding my LCS Square Body Pump as I write off my Healey 3000 (1961).  A repair kit should put you back on the road and it is not too high on the skill level providing you have the time. Sounds like a good winter project.  Be careful disassembling, mark everything, maybe take some photos and study the assembly as you go along.  I found the 6 screws securing the diaphram to the pump body on my pump were not even tight.  I suppose the diaphram (there was no gasket) had shrunk in those 50 years leaving the screws actually loose.  There is lots of help on this site if you need it and I may need some too, I'm not finished yet.

 

    

Daytona:  Thanks.  It's a 1961 MGA with original fuel pump.  Seems a rebuild is the answer.  Ed

I sent you a PM (message)

Ed,

On the Forums Page under Healey 3000 go to 'tech tip liabrary' and click onto fuel pumps 1 & 2.  Some interesting reading there that will be a lot of help to you.

 

John

 

Thanks to all for your advice