This seems to be a more common problem and one i had not been aware of before my own experience with it. Mine may also be a little different but could be the same. The problem for me is the pump. An intermittant problem where after i did a line purge test to see why my engine wouldnt start. At first no fuel, then as i raised the test voltage it would "pop". Then work perfectly all the way down to very low voltage. And start and restart at low voltage. Then put it all back and no go. Repeat the routine and raise the voltage and it would work again. These are multi commutator motors, and it seems that not all commutators work, with a little friction setting in with the interval of time. Just recieved a new pump so will test it out tonight. Interesting to see this problem expressed by so many persons at one time.