Fuel issues - using AMC pump and return

GrimGreaser

I have Airtex pump 60167 pumping up through a glass bowl filter with a return to the tank plumbed in. I tried a 0.030 orifice in the return and couldn't keep enough pressure in the lines to feed the carbs running up a hill. I blocked the return and it helped the hill climbing issue, but it would then vapor lock when stopped. So instead of the orifice, I put in about 14 inches of 1/16" tube. Now I hold about 5-6 psi at idle, but running up a gentle hill (35mph in 4th) I lose pressure after about a minute or so and it wants to stall. Letting off the foot-feed will bring it back after a bit. If I keep the rpms up (put in 3rd) I keep my pressure up and things seem fine. Seems it doesn't pump enough under 2000 rpm to fill the bowls. Could I have the pump shimmed too much? I have a ~1/4" spacer, but with that alone I would get clacking noise from the pump. I add a gasket and the noise goes away.

[Deleted User]

You could have a blocked fuel line in the tank. Are you using a AMC pump, which requires a 5/16 spacer? You may now have a bent pump arm, better check it. Walt.

GrimGreaser

Wasn't bent when I added the extra gasket, so I wasn't that far off. It was the same spacer I used with the original pump. Guess I'll pull the pickup tube to start.

[Deleted User]

GG - The Jeep fuel pump I have used is Airtex # 6737. # 60167 may be the same - ? Norm

GrimGreaser

The 6737 pump has a front facing inlet, the 60167 has a rear facing inlet. There's also one with a return already on it, 6748. If I hadn't of bought the one I did I would have gotten the return one... All with the same pump arm dimensions, provided the old hands I got the numbers from here are correct.

I removed the extra gasket, ~1/16", and it seemed better today. No noise or anything, either. I don't know - no apparent blockage between pump and tank. Guess I'll keep playing with my return setup.

[Deleted User]

You must have a restrictor in the return line, using a 30 thousand hole in it. This is to cause a little back pressure. Walt

GrimGreaser

I know. 0.030 didn't seem to work for me. Now I'm playing around with my setup. I don't have any other orifices so I'm using what I can. So far 6 inches of 1/16" tube is working.