Wilsons Sandbox

If using an in-line fuel filter with an electric pump of any brand, even those little square jobs, the filter must be on the pressure side (out-put). If the filter is on the suction side and becomes slightly clogged the pump will eventually fail. The points on the SU close to pull back the diaphragm to load the chamber with fuel, points then cam-over to 'off' (click) and the spring pushes the fuel to the carbies. If the suction side is restricted by a dirty filter or obstruction the points will hang-in there longer thus over heating and burning themselves out; even solid state modified points. And, if you have an old but working SU pump the diaphragm may not be long term compatible to the ethanol gasoline we have to use these days. My story ... if interested... Back in the 1970's when I used my '67 B/GT as an everyday driver I filled-up from an old-time gas station... and pumped in a lot of water and rust into the gas tank. I drained the tank and cleaned the carbies. But for the following several years the SU fuel pump would not last more then 8K miles. I tried every brand of electric pump on the market. Gremlins! I even installed two pumps with a 3-posiiton toggle switch behind the seat (center off position to foil potential car thief; including me sometimes). Dual pumps because I was afraid I'd be crossing the Golden Gate Bridge and have pump failure. The pumps did fail on busy roadways a couple times over the years and I would de-clutch and flick the ignition key on and off a few times to pulse the SU diaphragm...good for a 1/2 mile. I heard someone placed a turn signal relay on a shot SU as a pacemaker. Finally, I described the problem to Dave DuBois SU repair in Bremerton Wa. First thing he asked if I ever had a tank of 'bad gas'?...yes! Turns out there is a filter inside the MG B gas tank impossible to get to. With an extendible articulated mechanics mirror and 12V bulb dangling on a long wire (baffles) I saw a very clogged filter screen; entry thru' the fuel level float panel. Our TC tanks have a removable filter on the bottom; but empty the tank first. Dave's solid state SU conversions have been totally reliable for several years and miles on all my MGs since making sure the suction-side was completely open to the tank. Bill Traill San Jose, California.