<VV> YH Carb on my 1963 Spyder won't idle.

[Jeffrey Hennessey]

I am looking for suggestions as to why my Stock 1963 Spyder will not idle. I have a newly installed Clark's rebuilt Carb, as well as a new fuel pump. The problem is intermittent. It's little hard to start but will idle fine when it does eventually start. After driving a bit and parking for an hour or two, it may require a puff of ether to get going but will not idle. Driving on a highway at 65 plus, she sails right along. If I put her in neutral and coast, the RPM drops and shuts off, restarting instantly when I put it in gear and let out the clutch.  
Has anyone had a similar issue and how did you solve it. 
Thanks, 
Jeff