<VV> 140 running rich(?) need advise

[rbkj84 at comcast.net]

To the carb guru's out there in 'Vair land:

My late year production 65 Corsa 140 (with the 66 style carb linkages from the factory) has developed a problem.  Right side of the engine seems to run very rich.  But problem is intermittent.  Will run great for a while and then all of a sudden the RPM's will drop and it runs rough, with some white smoke ocassionally from that side.  Not blue oil smoke and valve seats are good based on compression testing, etc. Today it had that same problem after running great for several weeks and I parked it and can't get it restarted.  Can smell raw gas in that tailpipe.  Carbs were professionally rebuilt about 2 years ago by one of our respected VV vendors and they seemed to perform well. I was very pleased with the carbs which had a few efficiency mods done to them (nothing drastic or for racing only applications). Other symptoms that arise sporatically - right side exhaust seems much cooler than left when it is not running well.  Also, warm restarts (not hot restart immediately after shut d
own but if the car sits fors an hour or two) can be hard.

I want to look at the float level in the right side primary carb but because the problem is intermittant I can't see it as float - am I wrong?  Dirt in the carb somewhere?  Any assistance would be greatly appreciated.  
Thanks for any ideas.  I'll let you know the result when i get there.

Ron
65 Corsa 140 (with mild case of the blahs)
64 Spyder (recently back from Hot Rod power tour - too cool!)
1991 Buick Reatta