hey guys, i replaced the carb on my truck with a used one, well i put it on and it starts and idles great, just like a champ, now then, when i go to drive off it strugged kinds of lugs real hard, if i push on gas hard or quickly no matter how far it dies over, if i slowly rev the engine while driving or just parked it revs up fine till around 2500 or 3000 rpms, didn't do any of this with old carb, please give suggestions... thank you

 

What kind of carb? Sounds like it's not getting enough fuel. Did you replace your filter?

 

it's a little 2 barrel for a 2.8L v6, how can i check to see if it's getting enouph fuel?

 

I don't have much experience with 2 barrel carbs.....however it should follow the same principles. Hopefully others can join in to assist. Does that carb have a filter inside the main body like a Q-jet? Checking the fuel filter would be the first thing I'd do.

Next I would pull the air cleaner, get the engine warm operating temp, looking down inside the carb, crack the throttle linkage by hand, you should see a spray of fuel down inside the carb. If you do not it's not getting enough fuel to support open throttle runs. Some of the new "rebuilds" do not use viton rubber on the main metering jet, and power piston assembly. I have heard that todays grade of gasoline will "eat " the cheap rubber used on some of todays rebuilds in very short time. That may be some of your issue, but if you don't have fuel going down inside, I'd suspect something is not set up right inside the carb.

 

With that drastic of a driveability problem you will have to rejet. What 1983Zsled is refering to is the shot that the accelerator pump adds on throttle tip-in. This is only going to enrich the mixture as the carb transitions from the idling to main circuit inside the carb. With symptoms at 2500-3000 rpms, the problem is likely in the main circuit. Sounds lean. Does it backfire? Rejetting is a very easy task whether it's a dual-jet, or motorcraft. Do you have much experience in minor carb maintenance? Let us know what kind of carb it is and we can help further.

 

Sounds like the accelorator pump is not working if it's only when you tip or crack the throttle open. See you stomp the gas and the engine gets a huge gulp of air and if the accelorator pump isn't giving it a shot of fuel then it will stumble. If it cruises fine then it's not the jetting for sure and can only be the pump shot. As mentioned above make sure the "new" carb don't have a filter that's clogged.

 

if it revs fine in park up to 2500-3000, then falls flat, it's more than the accelerator pump.