Fuel Delivery Mystery - 62 Cat
 

My 62 Cat 389 2-BBL carb is not getting any fuel...it is bone dry. Filter is clear and have replaced the OEM pump with a Carter M6907 mechanical pump. Can blow low-pressure (5 psi) compressed air from the hose connected to the pump back to the tank thru the connecting line...hear a deep gurgling sound when I do this. When I attempt to blow low-pressure compressed air in the opposite direction, from tank to fuel pump, no gas comes out of the connecting line at the pump end. Shop manual doesn't indicate anything in the tank or line that would cause this. Will appreciate any advice on what the problem may be and how to fix it.

Question, How do you blow air from the tank forward to the fuel pump. How much gas is in the tank?

Place a large piece of duct tape over the tank filler pipe to seal the opening and cut a small slot in the tape. Insert rubber-tipped air gun into the slot & open the valve to admit the air. Tank is 3/4 full.

Had a similar problem to this myself. It's the filter sock inside the tank.

I was on the highway running at a steady 60-70mph when it failed. No fuel delivery.

We cured it by blowing air at a much higher pressure than 5psi through the delivery line. We took the fuel filler cap off first and you could hear the sock burst. You need to take the tank cap off first to ensure you don't damage anything by putting pressure into a sealed tank.

Problem solved but it was a pain to fix permanantly. Drop the tank, open it up, new sock, put it all back together again.....Good winter time job.

Drop the tank, get rid of the sock, and put a small inline filter in the tank hose just outside of the sender. If you use a clear one you can see when it;s dirty.

Don't use an inline filter in place of the sock. If a small piece of anything gets in the tank it can get sucked up against the filter's inlet and block it shutting off the fuel. I worked as a mechanic for many years and have seen this several times. Just buy a new sock and install it. The sock has such a large inlet area so it can't easily be blocked.

Yes, this is good advice. In my own case I fleetingly toyed with the thought that as we had obviously "torn" the sock by blowing compressed air back through it (it sure did make a sort of "whump" noise as it burst the sock), I thought well an extra in-line filter was the solution.

But commonsense prevailed and I dropped the tank. I was amazed to find a piece of old rag in the tank. Only about 4"x3". I guess someone years before me must have let it fall in there and it did no harm ever. But it might have done so in the future if I had no sock protection.:noidea::noidea: