049 starts but will not run past prime fuel

I am trying to revive a couple of old (30+) year old control line airplanes that I built in the 70"s. I disassembeled and rebuilt them both with kits from Cox. I replaced the fuel pick up tubes in both engines including the spring inside.
They both have integral tanks.
The engines start with a prime but then shut off within 20 or 20 seconds. All of the gaskets have been replaced but I reused the reed valves.

I have been screwing around with them for 2 weeks and can not get past this problem.

ANY IDEAS WOULD BE GREATLY APPREICATED.

Is the pickup tube supposed to go in the tank a certain way?
Is the reed tricky to get in properly? One reed has a clip and the other has a molded lip on the venturie tube.

Phil.

Phil,

For Control line the pickup goes in the 7-8 O’clock position.

Lots of reasons why it won’t run. Have you cleaned the backplate thoroughly? Make sure you can blow air from the backplate nipple to the venturi with the needle open.

What is your starting method? 20 seconds makes it sound like it’s running past prime.

Fuel used? How old?
Number of head gaskets?

Like I said lot’s of variables. We can get these things running for you. Stay tuned.