Choking a Rochester

[bmohan55]

Re-built my Rochester carb the other day, really made a big difference! Engine used to need the choke on much longer before it quite stumbling, now I can push it in within a minute or two (depending on temperature). My question is this, should I always give it a little choke on EVERY start-up? Yesterday (it was around 80 degrees) I started it warm w/o choke and drove about a mile and shut it off, stared it (w/o choke) about five minutes later and went about ½ mile and shut it off again for about 5 minutes (I was shopping). On start up it wouldn’t start w/o choke so I gave it some choke and it still wouldn’t start. Eventually I got it going by squirting a little carb cleaner in it, it ran great after that.

I’m being told by people not familiar with Rochesters that I may have had a bit of vapor lock in the carb and by not using the choke I didn’t get enough fuel to over come it. What do you experts think?

Sorry for the long post but I’m trying to fully understand how my truck works so I can intelligently diagnose future challenges.

thanks,
Bob

[badvibes]

Bob-

I'm running a Rochester on my '64. Are you sure you're getting fuel delivery consistently into the carb? The rest of the fuel system is up to snuff? I live in New Mexico and have run my truck in much hotter weather for short and longer periods of time and haven't had vapor lock issues. It doesn't sound like a vapor lock issue to me. I'd suspect something interfering with fuel delivery.

Good fuel filter, good fuel pump, no blockages in the fuel line? When I had a similar problem, I would drive about a mile then the truck would die. Wouldn't restart. After 20 or 30 minutes it would restart. Would idle fine in the driveway for an hour. Turned out I was missing the screen on the end of the pick-up tube in the gas tank. Enough gunk had accumulated in the pick-up tube that the truck could start but under load the carb couldn't get enough gas, the fuel bowl would eventually run dry and the truck would stall. Would finally restart, would idle just fine because it could get just enough fuel to maintain an idle. Got the pick-up tube cleared out and problem solved. Using the choke seemed to help keep it running at times but didn't cure the problem.

Jeff