Must have got a chunk of crud in the line when you changed pumps.

You can try one last desperate farmer trick before taking the top of the carb off.

Start the truck and let it idle with those idle mixture screws closed. Then with the air cleaner off use a good heavy screw driver handle and give a few raps on the 2 back corners of the carb top.

Here and here (red arrows)

[Linked Image]

That sounds corny as chit but you'd be surprised to learn how many float needle problems can be cured with a few raps directly above the needl/seat areas on the carb lol!!

You'll know if you've got it because the engine will run out of gas and die since you have the idle mixture screws closed.

If it works then you can crank your screws back out to there previous settings and you should be good to go.


Something clever here.