Trigg

Hello everyone, it has been along time since I've been on the forum, nearly 12 years if memory serves. But I'm back!!!


So the problem having. Long story short been working on this horse for the better part of 8 years. So here's the run down;


I am by no means a master of anything so if it seem obvious to you. Ask anyway cause I might have overlooked it or heck didn't even know about it.

Now keep in mind I'm somewhat of a bargain shopper so somethings are new and some used.


So I got tired of looking at it and wanted to start driving it. I put the holley red fuel pump on that I had from another project so its not new and to be honest it was really loud for a few weeks and for some reason it got really quite one day.

The carb is a Barry Grant and is well used and ill be honest I cant find a dang thing about it. Been driving it off and on for about 2 months now.


So here's the problem its bogging down while driving and really bad on a hard acceleration and I can feel and hear a sputter with light acceleration.

What I have done. At Temp I have adjusted both mixture screws equally to get max vacuum which is between 14-15 with a target rpm of 750-800. I never got a truly steady vacuum reading and the rpms fluctuate with a mixture of 50 up and down.

The Carb adjustment screws are 2 1/8 out evenly total. 1/8th was turned in have more steady street driving. I started this process with the screws 1 full turn out from bottom.

The firing order is correct, plugs are good, and wires look great.

The tank is new and new fuel filters. The holley red fuel pump is used and loud but it suddenly got quite. But the noise didn't seem to make a difference in pump function.

To the best of my searching I haven't located a Vacuum leak yet. But I'm always on the hunt.

Motor doesn't knock and no noticeable valve clatter.

Im not much of a carb guy but i'd like to get this one working properly for a least a few more months until i throw EFI on it.

Thanks for the input and advice.



67 Coupe no ps/pb/ac


MOTOR

351c Stock bottom end

Stock Heads 2v

Cam is a stock/mild - not even sure of the brand on the cam

Weiand X-Celerator Intake

BG Demon what I believe to be a Road Demon JR 625 with manual choke and mechanical secondaries.

Mallory Promaster Coil

Mallory Unilite Distributor

Holley Red Fuel pump at 5psi


Trans

C4 built by Dynamic

2500 Stall


Rear

8.8 with 3.55 posi

Stepman

I would go back to the mixture screws and turn them in 1/8th at a time. Allow it to settle between turns. Keep turning until you hear it start to stumble and stop. Then turn each one back out 1/4 turn. That should be where you want to be. How's your timing? Sounds like it may be a bit slow. I'd start with that at 10 degrees base and see what that does.

barnett468

did you rebuild the carb?

please explain the statement below better.

"So here's the problem its bogging down while driving and really bad on a hard acceleration..."

the idle circuit has no affect on throttle positions above around 1/8th.

check the timing at idle as was suggested but check it with and without the distributor vacuum chamber hoses connected. after this, disconnect the hoses and plug them and leave them disconnected.

tell us if it has a single or dual distributor vacuum chamber.

post the timing info.

as far as the miss goes, it may have bad plug wires or a bad plug.

Trigg

Sorry fro taking so long to get back, I've been swamped.

Timing is at 14 and all at 32 at 3000rpm

I did find a bad plug wire which was giving a misfire on No3. I changed all the wires and rechecked gap at .40 there Autolite AR34 if that makes a difference.

"So here's the problem its bogging down while driving and really bad on a hard acceleration..."
If I'm at a stop and go to accelerate it'll loose power and the more throttle I give it the worse it gets. If I let off and really ease into it, it will accelerate but it hesitates "sputters I suppose"

The distributor isn't a vacuum style.

Im starting to think its a power valve or jets something with the carb. I did rebuild it a few days ago but its still doing it.
I drove it today and it drove great for about a hour. Got home loaded up the family to go to a car show and it started doing it again as soon as I started it. Drove it to the car show and back to the house and it was doing it the whole way.

As I sit here thinking about it. It ran fine with the air filter off. "I've got one of those force air scoop contraptions". The filter doesn't even have 500 miles on it so I know its not bad. mmmmm....

barnett468

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barnett468

well, then it is obviously the filter or filter base possibly hitting the choke linkage and holding it partially closed.