049 starts but will not run past prime fuel

phcanfora@aol.com Mon May 11, 2020 11:36 pm

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.

**Cribbs74** Mon May 11, 2020 11:48 pm

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.

Oldenginerod Tue May 12, 2020 6:49 am

Welcome Phil.
I know you said you replaced all the gaskets, but did you replace the small rubber gasket on the venturi tube as well? This one can be easily overlooked.

phcanfora@aol.com Tue May 12, 2020 10:27 am

Yes, I bought a kit and it had that in it. There was no o ring there but I figured it out.

Maybe I put it in the wrong place.

phcanfora@aol.com Sat May 16, 2020 12:43 am

Yes... you hit the nail on the head! IT WAS THE BACKING PLATE. I cleaned it and blew it out. Now the engine starts and runs fine.

Thank all of you for your help and suggestions!
Phil

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049 starts but will not run past prime fuel

049 starts but will not run past prime fuel

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Re: 049 starts but will not run past prime fuel

Re: 049 starts but will not run past prime fuel

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Re: 049 starts but will not run past prime fuel