Help! Hesitation to Accelerate

[Smittysduster]

I'm new on this website and equally an amateur when it come to working on my car. I recently bought a 72 Plymouth duster with a 318 in it. It has an after market edelbrock four barrel carb that the previous owner put on it. The problem I'm having is that when I put my foot on the gas, I get a hesitation to accelerate, however if I already have my foot on the gas it works fine. I have already replaced the distributor, fuel pump, and fuel filter and am stumped on what to do. Any advice or help is appreciated!

 

[kennygene]

Make sure your timing is set correctly. I tried tuning an edelbrock on mine but wound up switching to a Holley. You will need to know your cam size and compression to get the timing perfected.

 

[Smittysduster]

I used a timing gun to get my engine timing right, is there any chance my carb could be causing the issue entirely? It was installed before I got the car and I don't think it was made for my engine based on some of the hardware they have on it.

 

[RedFish]

Look for the initial shot from accelerator pump on the carb. That little pumps failure and subsequent hesitation is somewhat typical for any carb.

 

[kennygene]

What did you set the initial timing at? What is the total timing without the vacuum?

 

[crackedback]

What did you set the initial timing at? What is the total timing without the vacuum?

Agreed. If you are going by the book for initial timing it won't run best it can. Set it at ~12* and see if it's snappier.

There are a ton of threads about setting timing, search for a few.

Lots of "carb" issues aren't carb issues at all.

 

[kennygene]

You have to get the timing right before starting on the carb. I was taught timing before carburetion.

 

[kennygene]

Mine is set at 12 deg at idle and 34 def total all in around 3 grand rpms. My vacuum advance is hooked directly to the intake manifold vacuum and total timing with vacuum runs around 60 deg. I had to buy a timing limiter from 4 secondsflat to get the total mechanical timing to work properly.

 

[Smittysduster]

Look for the initial shot from accelerator pump on the carb. That little pumps failure and subsequent hesitation is somewhat typical for any carb.

I've adjusted the accelerator to pump to all three positions but it hasn't made it much better any which way. Is there a chance the whole pump is bad?

I'm going to have to redo my timing, I'll see what I can do this weekend.

 

[tekslk]

Yes theres a chance actually look down the carb and work your linkage like you were stepping on the gas, you should see a nice squirt immediately, If not it isnt working right and something is broke or out of adjustment.