so I went ahead and picked up a brand new carter YF 1 barrel on eBay for my '84 f150 (duraspark converted 300 six). Of course it's probably a Chinese copy, but I've been having problems with crappy rebuilds with worn out original carbs. I put the eBay carb on and it starts and idles great, cruises great, but has a nasty hesitation or flat spot when tipping into the accelerator while leaving from a stop. The idle mix has been adjusted perfectly with a vacuum gauge. I can look down the throat of the carb and I see a stream coming from the accelerator pump when I move the throttle, but it's not a very strong stream. What can I do to remedy this problem? My original worn out, leaky carter is smoother in take off than this one! Thanks for any info!

 

See if there is another hole you can put the accelerator pump lever in to give you more of a shot of gas when the throttle lever is moved. Some carbs have extra holes for this.

 

I stumbled on this link. I didn't look in there too hard, but maybe you can find something helpful.

Carter YF YFA Carburetor | Mikes Carburetor Parts

 

cold or warmed up ?

 

Thank you for the link! I check out the videos and whatnot, but nothing was specific to the hesitation. I may have to tear into this thing, but I really don't want to since its a brand new carb. The hesitation happens no matter if the engine is cold or at operating temp.

 

Think I'd adjust the idle screws.