Hey guys, my truck has a hesitation problem at low rpm's that it has always done, even when the engine was freshly rebuilt.

At idle to about 1500rpm it hesitates. It's noticeable when shifting at 2000-2500ish rpm's. Is this considered normal? I've just lived with it, but now I'm starting to wonder if it just that the carb needs to be tuned better?

The truck is a 79 F250 4x4, 4 speed with a 400, balanced & blue printed, high compression, Edlebrock intake, heads have been ported and polished, it has a cam, and also a Carter 650 carb.

The truck runs great and feels strong, it just hesitates a little at lower rpms.

Thanks.

 

Was the carb ever tuned for your specific application or was it just "plug-n-play" right outta the box?

I'd experiment with different metering rods, step-up springs, jets, accelerator pump hole location, etc., get the carb dialed in to work with your particular setup.

If you don't already own the hard copy the manual is available for download online that explains all the above, it's pretty simple, just a lot of trial an error is all.

 

I'm not extremely knowledgeable on engines and performance but it seems to me like you're carb might be a little small for all the modifications done. I could be wrong though

 

I know that the adjustment screws have been messed around with when we put the engine in and I believe that the jetting was changed as well, but I'm not sure.

I don't know much about carbs at all. But I would like to learn, is this something that I dare learn about and start adjusting? I would rather not learn the hard way and screw up my motor from tinkering when I should have had someone do it that knows what they are doing.

 

if you go ahead and get a full adjustment kit with all the sizes of rods/jets and stuff all you have to do figure out what it has currently, change one thing out for the next bigger/smaller size at a time until it gets better, if worse then you know you went the wrong way. pretty simple to do. carter's are pretty much edelbrocks and they have youtube videos that show how so you shouldnt have any problems

 

I guess as soon as it warms up I'll have something to mess around with then.