When I first got the old MGB running again about a month ago the biggest problem we had (other than gas leaking from almost every possible location!) was getting the old SU fuel pump to work. Initially it wouldn’t run at all but after taking it apart and cleaning the breaker points it finally came to life. I certainly wouldn’t trust the old SU at this point but after being reinstalled it worked fine, fuel pumping like crazy to the carburetors and all over the floor of the garage. At least the old MGB started.
The fuel leak this time was from the overflow on the SU carburetors, one of the float jets being stuck in the open position. A serious cleaning job on the jet and at least it would shut off when required. We did notice that one of the overflow pipes that channels any overflow fuel to the road was missing, not a good situation as any overflow from that particular carburetor drops directly on the hot exhaust system. Apparently this isn’t that uncommon; poof, no more MGB!
One week later and no fuel, the old SU fuel pump had given up again. It’s not exactly easy to find a SU fuel pump where I live and with the Canadian peso being so low (65 cents US) the exchange rate is beginning to kill us. Time to look for an alternative. Even finding a low pressure fuel pump turned into a chore, most of the stores in the area catering to the big block V8 crowd. This MGB is also still positive ground! I finally found this little Mr. Gasket Micro Electric Fuel Pump and for $40 and figured if I killed it at least it didn’t cost much, it’s also specifically labelled as negative ground only. Finding the proper fittings was impossible locally so I cut the British standard fitting off the fuel line and switched over to 5/16 fuel line. The pump is located inside the battery box which works well. So far so good.
I came to the conclusion that if the pump were isolated from the MGB frame I would be able to just switch the wires and everything should work. Wrong! The strange thing is when I touched the positive lead of the pump directly to the chassis the pump runs. I still don’t understand this but it works and I now have fuel. My only concern is that the pump won’t shut off if a fuel line were to break but apparently this is common with many electric fuel pumps. I’ll likely switch back to the SU fuel pump at some point but this will work for now.
Here’s where the fun begins. The pump is providing fuel to the carburetor apparently at a slightly higher pressure than the old SU pumps and while the carburetors themselves don’t care the old fuel lines did. Once again the car started well and was running smoothly but once again gas is leaking all over the place, this time from the fuel hoses feeding the carburetor. Time to change the old original fuel lines in the engine compartment, at least it’s inexpensive.