K-Jet no start

I have a 76 242 that is all original. Recently it was getting harder to start, I have replaced the main fuel pump, accumulator and the starter but not much has changed. I can get it to fire sometimes and with my foot on the gas it will run briefly. Then it usually dies and won't start. If I let it rest a few minutes I can often repeat the process. Warm up regulator maybe? Does anyone know what the adjustment screw on the throttle body does? I fiddled with it without actually knowing what it does.

I would definitely get the kjet pressure gauge setup and test your control pressure regulator. If it clogs it makes the engine too lean. This will make it hard to start and stall over and over on a cold start. Kjet has three functioning fuel tests. Main system pressure, control pressure, and rest pressure. Control pressure directly influences the engine fuel mixture and can cause running and starting problems if it's not correct.

The adjustsment screw on the throttle body is to prevent the throttle plate when closed from contacting the inside of the throttle body. It should be adjusted so it lets the throttle body close. Usually, that is tighten the screw till it just contacts the throttle arm. Then about 1/4 a quarter to and 1/8 turn against the the throttle arm sets it. Your idle speed is adjusted with the thumb screw under the front of the intake manifold.

Be sure the rubber boot between the throttle body and the air flow sensor is sealed and in good condition. If that isn't sealed it creates a large vacuum leak that can also cause issues like you describe.

Thanks for the response dl. I have been resisting buying a pressure testing setup but maybe I should at this point.

Funny you should mention the rubber boot, as I was replacing the starter I noticed it had come loose on the bottom end. Looking into it I found all three rubber mounts for the air flow meter were broken! The only thing holding the meter on was the rubber boot itself! It was like that the last time I was able to drive it. I replaced the rubber mounts and fixed the boot and it won't stay running since then.