Is it electrical or gas?

[Rob Doe]

Well I borrowed another carburetor from a club member and the problem went away. So we're going to go back and double check my carburetor again.
Thanks again for all the helpful answers for my problem. When we find the source, I'll add it onto this post for future reference.

Gary, now that you're sure its fuel, I can add one last idea. My coupe had the 'start, run a short time and die' problem too. I had removed, cleaned and measured the jets. I eventually found that the cap jet was leaking at its base where the gasket is. I discovered this by using my longest finger and touching the jets to find out why the carb intake area was wet. I had a small camera for the phone and ultimately looked inside. I switched from the little red gaskets to the black ones from Brattons and the leaking stopped.

 

[Gary57210]

That will be something for me to check. Thank you

 

[Patrick L.]

To get all the passages clean I use Deep-Creep spray and compressed air to make sure all are clear, even if its been soaked in cleaner.

Its good to remove all the jets, but, if I think one will break then I leave it in. Once you get good air flow thru everything then it should be go to go.

 

[Gary57210]

Hopefully I found the problem. I was going through and changing the jets with new ones. When I measured the old main jet it was between a #76-78. My search showed that it should be from #63-64. After changing it the problem seems to have gone away. time will tell. I have attached pictures of the old jet. It has a 11 stamped on it.

 

[katy]

My notes tell me that a #11 jet is .0216535", the main jet should be a #20, .03937"
The idling jet should be a #11
See: http://modelabasics.com/carb basics 2.htm
Also: https://www.polysource.ca/drill-bit...MI6s7W4JnO-AIV1RitBh0Mkg-PEAAYASAAEgJhj_D_BwE

 

[Patrick L.]

Hmm, interesting. I guess anything can happen over all these decades.

 

[JoeCB]

First thought ... the carb float is sticking up and'/ or the needle is sticking closed
Joe B