hi guys, I need some help on carb issues. I have a 1973 F250 with a 360 and a Motorcraft 2150, I rebuilt it a couple weeks ago and cant seem to adjust my way our of this off idle hesitation issue. I double checked the timing to ensure it was at OEM specs- that was good, I set the air/fuel mixture with my vacuum gauge ( at temp with vacuum advance disconnected)- that was great, no vacuum leaks, other then the off idle hesitation it runs great...like really great. I did notice if I drive it while the fast idle cam and choke are still engaged it doesn't have that hesitation. My thoughts are: with the choke on, its enriching the fuel mixture and decreasing the air, so the hesitation goes away due to the increased amount of fuel- does that make sense? so, I've adjusted the arm on the accelerator pump in a few different positions, currently its on the outer hole on the pump arm and the highest hole on the travel-over lever, it seems to like this position best. As far as getting more fuel to the carb, I'm out of options unless I re-jet it, right?. its the OEM carb, I cant imagine why it would now need larger jets? anyone have any advise? one thing to note is, it does have hefty exhaust leak, I don't know if that would effect anything? I plan to seal that up this weekend and see if that works some magic. Any advise would be great guys! thank you in advance!

 

When you set the vacuum did you got for highest reading and then richen it out +1Hg" ? What hole did you put your accelerator pump arm in?

 

when setting the vacuum, I threaded the air/fuel screws in *gently, and backed them out 1 1/4 turns as a starting point, then hooked up the gauge and turned them out about 1 full turn to get the best vacuum if I remember correctly, then I turned them clockwise 1/4 each ( this is what the OEM manual specified). sorry, I'm not familiar with +1hg? can you educated me on that ? the accelerator pump arm is on the outer hole on the pump and the #4 position on the traveler arm. thank you for your help!

 

So, if all was well before you rebuilt your carb, then I’m guessing something may have gone wrong.
When you rebuilt, you checked/sprayed through all the orifices/holes/ etc.
All the parts go back in the way they came out ? Check Ball ?
You replaced the enrichment valve & gasket ?
I’m assuming your transfer slot is not blocked if it wasn’t before.
Great spray out of the accelerator pump ?

What do your spark plugs look like?