Problem Idling After Not Running For a Month

[Mr_T]

Howdy:

I just finished bolting everything back in place after replacing the clutch and flywheel on my 78 GMC K15. The job took longer than I had anticipated between work and vacation and the truck hasn't run for about 1.5 months. Now when I turn it over it will start but is rough and won't stay running without some light gas pedal. As the engine warms it has a harder time staying alive so I haven't run it for more than 30 seconds at a time. I've turned it over a few times over a few days and the situation hasn't improved.

It's getting gas but the gas is a little old. I put some stabilizer in the primary tank and put about a gallon of fresh gas in the nearly empty secondary tank. I've been starting it with the secondary tank.

I replaced the spark plugs today one by one and squirted some oil inside each cylinder to make sure they're getting lubed since I figure the oil is sitting at the bottom of the pan.

I removed, cleaned, and reinstalled the after market fuel filter just before the carburetor.

No results and I'm fresh out of ideas after browsing the repair manual and the forums. Any recommendations?