wheres my gas going

i have a 73 ford 390 i have replaced all the parts of my fuel system and now when i let my truck sit for a few days the gas runs out of the filter and back in to the tank i can see it becuase i have a clear gas filter housing. i have to prime the carb. every time i try to start it. i am guessing that the gas runs back in to the tank but i am not sure how to stop this and why it does this so if you guys could help me i would be really thankful


thanks jacob

 

Could be the fuel pump, there's a check valve in there that should prevent reverse flow. Or... a loose fitting between the tank and the fuel pump that dont' show because the pump pumps faster than the leak so after it's running, the pump pulls a little bit of air that you don't know about. Then when you shut it down gravity pulls the gas back to the tank, the line eventually fills with air. How to find it; park it with the front end down hill with the tank above the fuel tank level. After a while the leak/seep will appear as a wet spot somewhere between the motor and tank.

 

thanks for you help i will try that happy motoring and have a good thanksgiving

jacob

 

This happened to me, after about 2 years I found out it was {Road Gremlins} sneaking in my garage at night and ****ing out the gas, I think they where trying to get high off the gas fumes.???????

 

All my junk does this, thats why I put an electric fuel pump on everything I own. NAPA has some nice small, qiite, ones that you mount next to the fuel tank for around $30. I run the hot wire off my ignition switch. Turn the key on, give it a 20 seconds, start the motor. I know I should probably run the wiring through a relay tied to the oil pressure fiting, but I don't want to screw around cranking the motor to get oil pressure. Maybe someday after I burn down a car I might rethink that thought, but until then, I'll do it like I have been.

Gene

 

I have a 73 ford f250 with the 390 also. Mine did the same thing as yours. I thought there was a leak also but could not find one. I was going to rebuilt my carb, I grabed the inet fuel filter fitting to pull the fuel line off it snaped right offof the carb. I had never seen the fitting leak but it was cracked right at the threads. Since I replaced it it has not done it since.

Jonney

 

You have an air leak. And it's high up somewhere. Fuel does not leak out, air leaks in.

 

Could be running into your crankcase. Especially if you have to prime it. The pump should pump it up to the carb just fine.

Check and see if its makeing oil.

Bad fuel pump diaphragm =poor fuel pickup and leaking into the crankcase.