fuel pump

Here's another little problem that I am wondering about. My CJ has a glass fuel filter in it so I can see the fuel before it goes into the carb. Last year, I do not remember having any trouble starting the engine due to lack of fuel. Recently, the fuel drains back to the fuel pump and it takes quite a bit of cranking to get the fuel back into the carb so that it will start. Today, I replaced the fuel pump, drove around a while, and parked it in the garage. I went out a little while later and the filter was empty again. It has a 1976 AMC 360 with the mechanical fuel pump. I'll probably replace the mechanical fuel pump with an electronic one eventually. I'm just hoping that I'll not have to replace the starter due to this problem. Kind of a pain to keep lifting the hood to pour gasoline in the carb to start it after it sits overnight.

Chip

The proper filter has two outlets to prevent vapor lock. The center outlet goes to the carb and the 'top' outlet goes to the return line. If the return line outlet isn't at the top, it will allow the gas to syphon back to the tank when it site air locking it so it acts like you describe.

If you only have one outlet, you will have vapor lock issues, but the fuel draining back is caused 'usually' from a pinhole in the line on the suction side of the pump. This allows air in when it sits, vapor locking it, but won't leak much due to being a suction line. Normally the leaks are near where the rubber lines hook to the steel ones at the clip on the frame either at the back or front. It will only show as a small stain at first.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Chip wrote: