I've had a '78 348 for a couple of years now and no matter what I do, it's very hard to start when cold. And the colder the air temperature is, the more difficult it becomes, to the point that it just won't start at all when the air temperature is below 40F. When warm, it runs great, just super. I replaced the old Amal carb a year ago  with an OKO from Mid-Atlantic, so it should be jetted properly. Power delivery from low RPMs on up is smooth. Once warm, it idles reliably, and re-starts are no problem. 

 

Generally, my starting procedure is this: Choke on, no throttle, kick it 3-5 times and it starts, but if I add any throttle, it dies. It dies on its own after 5-15 seconds. I repeat this process and each time it stays running a little longer. After about five times doing this, I can turn off the choke and add throttle and it won't die. Then I rev it for a couple of minutes until it's fully warmed up. Then it runs great.

 

Why would it do this? Any ideas?

Edited September 30, 201510 yr by behyer

Your problem is really easy to solve. Just clean the starter pilot that is located at the bottom of a hole in the carburettor's float chamber bowl. You'll need a 4x1 mm screwdriver.

 That was the same problem with the  Amal. The pilot would plug up quite easily.