two barrel troubleshooting

[Drives a 5]

I need some help with my Holley 2300. After I swapped from the one barrel it ran great for quite a while, all I had to do was a jet change and some accel. pump arm adjustments. A while ago though, I went out and it just started idling rough (surging) and cold starting & running took a dive. I can't figure out what caused this as I hadn't made any changes. I took the carb apart, cleaned it, readjusted idle stop and mixture screws and the idle is ok, but startup is much worse than it used to be. I have to start it 3 or 4 times to get it to idle and not die and it wants to die when I accelerate. It does run pretty normal once it's warmed up though. Anyone have ideas on what to check? It's my daily driver so thanks for any help!

 

[matt1967]

surging is a vac leak. our 6's like vac, leaks kill the power and the idle quality, couple that with a hot cam and it might not even idle.

 

[Drives a 5]

It only surged initially - I did replace all the lines, there were some old ones. Anyway, it doesn't surge anymore, just the cold starting/drivability etc. problems so I don't think it's a vac leak. Also carb cleaner doesn't find any and I hear no hissing... any other ideas?

 

[80Stang]

Power valve gone bad?

 

[Drives a 5]

Put a brand new one in yesterday, no change. Any other suggestions? Please?

 

[wsa111]

Scott, what carb do you have, the 4412-500 or the 7448-350??

I assume you have an automatic choke, please advise.

What camshaft are you running???

If you have other than a stock camshaft do you have the vacuum advance connected to full manifold vacuum, need all the info then i maybe able to help your concern.

 

[Drives a 5]

It's the 350cfm, but it's a side hung float, not center hung - I think it might be a different number than 7448, I'll have to see if I can find it... can't remember.

It's a manual choke that I don't use much. It used to start up and idle good just at lower rpm until warm and then it was good to go, no choke needed and the weather hasn't changed since before.

Stock cam from 82 and the carb only has the one vac. port so yeah it's hooked up to full man. vac. Never gave me any problems before... Thanks!

 

[wsa111]

Scott, since its not a 7448-350 with an automatic choke, all i can say the cold driveability is in the position of the manual choke.

If you had an auto choke i may have been able to help, sorry

 

[Drives a 5]

Thanks - I posted up on carbdford as well and I "think" all it is was it was idling too lean (only tested it once so far though, we'll see after it's totally cold tomorrow morning). Everything I read about setting the idle said go til vac & rpm is at the max and no further or it'll be too rich ... but that was no good, I guess my car likes it richer!