Carb Problems

[sinisterstang65]

Ive got a 351W with a Holley Street Avenger 670cfm, and just got the motor dialed in, but the idle runs perfect, but its once you drop it into gear, the idle just drops, and when you go around a turn or slow down too fast, it dies. Ive had numerous people tell me to go to a Edelbrock 750, bc this car is mostly for daily driving. But i would like to figure out what is wrong with it, so i dont hvae to buy a new carb. Any info would be helpful, need it as fast as i can. Thanks

 

[jcode68]

Could be a number of things including the idle being set too low, fuel bowl levels too low, vacuum issue. Are you sure the carb is hooked up properly? Is your vacuum advance on the distributor connected to the port vacuum line? I would have someone familiar with carb tuning go through and set it up. I use the 670 Street Avenger and it's a really good working carb for street driven cars IMO.

 

[sinisterstang65]

RE

Yea its hooked up right, and we even brought it to a mechanic who specializes with holley carbs, but the idle is set right, and it idles perfectly when it is in park, but its once u drop it into drive or reverse, it just drops. And the bowls are set right, and we set it to the right depth, and the vaccum is also fine, i mean its a possibility there is a crack or hole, but i really dont think thats it. We also rejetted it, and completely had it rebuilt and had a mechanic dial it in, after we set it up. So does anyone else no of any possiblities it could be???

 

[D.Hearne]

Edelbrocks are no better street carbs than any Holley is. (God, I get tired of hearing that crap)Anyone who tells you that is full of s--t. My money is the float level is too low and/or the idle mixture is too lean. Could also be the timing is retarded too much. Just because you brought it to a mechanic who "set it right" tells me it's not "set right" You're all over the place in your desciptions too. That's part of your problem. It's set right , but it's not. Then you say it's got a crank or a hole, but then you say it's not that either ?

 

[tx65coupe]

I seriously doubt you need to go to a 750. The 670 carb you have now should be a good match for you 351. I bet something just needs some adjustment.

 

[sinisterstang65]

RE

Alright, well im only 16, so my description is not going to be as good as people who have been working on them there whole life. But we have had 3 different mechanics work on the carb, and the last one has the idel running great in park, its once you put it into drive or reverse the idle drops. Thats what we cant figure out, because we know the float and idle is set right bc it runs fine in park. We just cant figure out why it dies when we are slowing down or going around a turn. Il say it again, i know the idle is fine in park, but its once you put it into drive or reverse it get sloppy, so thats what we want to see if anyone has any ideas on what it could be.

 

[woodsnake]

The idle speed itself isn't the problem here. It should drop when you put it in gear. The question is more of over all tune. Where is your timing set? What is the idle speed RPM's in park? When you set the timing, did you disconnect the vacuum advance from the distributor?
You should have ~10-12~ degree's initial timing, idle in park at around 700-800 rpm. When you drop it in gear, it should be around ~600~ rpm.
If you don't know the specific numbers for the timing or RPM's, then you can't fix the problem.

Tuning by ear is fine for some things, tuning for performance requires actual numbers......

 

[D.Hearne]

The idle speed itself isn't the problem here. It should drop when you put it in gear. The question is more of over all tune. Where is your timing set? What is the idle speed RPM's in park? When you set the timing, did you disconnect the vacuum advance from the distributor?
You should have ~10-12~ degree's initial timing, idle in park at around 700-800 rpm. When you drop it in gear, it should be around ~600~ rpm.
If you don't know the specific numbers for the timing or RPM's, then you can't fix the problem.

Tuning by ear is fine for some things, tuning for performance requires actual numbers......

Listen to the man, he knows his s--t......... Couldn't have said it better myself.

 

[D.Hearne]

Alright, well im only 16, so my description is not going to be as good as people who have been working on them there whole life. But we have had 3 different mechanics work on the carb, and the last one has the idel running great in park, its once you put it into drive or reverse the idle drops. Thats what we cant figure out, because we know the float and idle is set right bc it runs fine in park. We just cant figure out why it dies when we are slowing down or going around a turn. Il say it again, i know the idle is fine in park, but its once you put it into drive or reverse it get sloppy, so thats what we want to see if anyone has any ideas on what it could be.

As woodsnake alreadt posted, the idle is supposed to drop when put into gear. The cornering and braking part is directly related to float settings. It's either too high or too low.