Bruce,
Just another very easy thing to check, but since you're having cold start issues it definitely could be the culprit. Remove the two small output hoses from your primer solenoid and make sure it's actually pushing fuel thorugh when you push in the key switch. I recently had to replace mine b/c the internal seals died and the solenoid wasn't pumping when it was supposed to (even though it WAS clicking), and was also free-flowing fuel when running b/c the fuel pump would push extra fuel right through the solenoid and into the carbs.