318 rebuild/overhaul kit

The choke plate is closed shut or close to shut when you cold start; that creates a vacuum in the main throat of the carb and pulls in extra fuel to help the engine run rich, which is needed cold. It also should kick open the throttle a bit for fast idle speed. Having a manual (cable) choke is good in that the normal electical or thermal devices that set and then gradually pull off the choke during warm-up are bypassed; they typically are not functional by now. Now, you just need to learn how to use it!

• Pull on the choke when cold; it takes more choking (closed tighter) the colder it gets.
• Pump the throttle 3-4 times, then start. It ought to 'catch' and run.
• If it wants to stumble and die, then either:
  • Pump throttle over an over; this use the accelerator pump to put in more fuel if it needs enriching
  • Adjust the choke to more or less to smooth the cold idle. As the engine warms you gradually pull of the choke. You'll get the hang of it.

Yes, sounds like a busted diaphragm! The HEI sounds like an excellent idea and you can sell it later on. If you set the relutor gao, use a brass or non-magenetic feeler gauge to avoid 'addling' the reluctor. 3 thicknesses of standard copy paper is pretty close... The gunk could be from a lot of things, including fuel in the oil.

And yes, it should squirt fuel down the throat(s) when you flip the throttle... that is the accelerator pump at work. Carbs run lean for a moment when you open the throttle, even just a bit, and the accelerator pump puts in extra fuel to cover that momentary lean situation, until the carb re-stabilizes to the increased airflow.

Yep, there's one way to do stuff..... and numerous ways to mess up LOL