Fuel Pump Notes

Having decided that I must solder up a couple of ‘olives’ on the fuel supply pipes that have been loose for 10 years, but not leaking any fuel that I knew off, I took the further decision that I might just as well give the whole fuel system a good clean out – the carburettor and pump are normally done annually, if there’s no unscheduled blockages during the year!

Both the carburettor bowl and the fuel pump needed a good clean out of fine powder (I normally scrape the silt out and use plenty of petrol to wash and clean the parts in).  The fuel pump is held to the crankcase by two nuts onto studs in the crankcase, or at least they were originally.  I have studs on one engine and bolts on another, however this note is about the studs.

When I took the nuts and spring washers off the pump studs, the pump although moving slightly was not going to come off, because the constant thumping of the pump mechanism and me tightening up the nuts every so often had compressed the Masak metal into the threads of the studs.  After about 20 min's I managed to loosen the pump enough to get it over the stud threads (another ‘dreckly’ job…).  I had not resorted to a chisel between the crankcase and the pump, because after 70 years the pump moulding is likely to be tending to the brittle state and the last thing I wanted was a broken ‘foot’ on the pump.  When I put the pump back on the car I used a large flat washer under the spring washer and nut to try and spread the load.

fuel p4

The photo shows the depression caused by the spring washer into the moulding at ‘A’, it doesn't look a lot, but after 20 minutes......... ‘B’ is a normal pump ‘foot’.

For those of an Anorak nature, pump ‘A’ is a ‘U’ type with priming pump lever and ‘B’ is a the plain ‘M’ type – I know ‘T’ is the normal one associated with the Seven engine, but the engine had a ‘U’ when I bought this set-up in 1963, and it works, so I don't meddle.

E.& O.E.


This article, written by Sandy Croall, originally appeared in CA7C Seven Focus in June 2009 p19.