Hard start cold - possible fuel issue

[tip]

I recently picked up an 86 C30 with a 350 and 105K miles. I'm having a hard/no start cold.

It won't start after sitting for a day or so. I can get it running by adding a little fuel into the carb. It dies, I go out and put a little more in. It starts and dies again. I repeat this about 3-4 times. Once I get it going and warmed up, I can let it sit for an hour and it will start right up. Runs great.

The guy I got it from said the gas was 2-3 years old, so of course that's what I thought it was. I ran out the left tank and let the right tank (which was FULL) run down about 3/4 then I added 2.5 gallons of 92 octane, fuel stabilizer, checked spark, cleaned plugs, charged battery, replaced the in-carb fuel filter and drove it/let it run for about an hour and let it sit overnight.

So I go out this afternoon and pulled off the air cleaner before I try to start it. I move the linkage by hand and watch, slim to none fuel squirting out. I do it over and over again and no still not only more than a few tiny drops of fuel and "hiss" "hiss".

So I added some gas to the carb as usual and she fired up after the third bit of fuel added. Let it warm up for 5 or so minutes. Shut it off. Now I look in the carb and plenty of fuel comes out when I manually work the linkage. Starts right up no problem.

So, my question is: Is there some sort of check valve in the mechanical pump or somewhere to not let the fuel drain out of the carb? Fuel should be staying in the carb after its shut off right?

Thanks, I haven't had a carbed rig in a while.