Need a carb / vacuum wizard BAD (newbie!)
truk820
Jeeper
I’m having some serious frustrations with figuring out a rough idling problem and I decided I’m going to turn to the wizards on the forum (and apologies for being a novice!).
I’m running a GM 151 Iron Duke with a 2 barrel Rochester carb. I fired the engine up for the first time in a few months and it runs rough – very rough – and if I don’t continually give it gas it will stall. I contacted the PO who informed me that after he had the carb rebuilt and installed it had vacuum problems but “he’s not a mechanic and his friend knew enough to plug a few lines” to get it to start. He never drove it after the carb was installed and I bought it shortly thereafter.
My previous post mentioned a potential starter relay problem but essentially it could be anything…however seeing the SheetRock screws makes me uneasy, as does the charcoal canister not being hooked up.
So I’ve decided to run the current setup by you guys and see if you can help me out. If possible I’d like to hook the charcoal canister back up.
I labeled the picture here with some letters and numbers I hope you can follow:
In summary:
On the opposite side (the driver side) of the carb there’s a rigid hose that goes to the valve cover. The PCV valve on the valve cover is connected to the air cleaner assembly.
I pulled the charcoal canister and after some scrubbing found the 3 ports are labeled (from L to R) PCV, Fuel Tank, Carb Bowl.
So…what do you think goes where? And what should I do with the PCV port on the charcoal canister if the line is going to the air cleaner assembly?
Also here’s a picture looking down on the carb, taken from leaning over the passenger wheel:
Anything look fishy? I know it’s a bit of a long shot diagnosing these things virtually but any help is appreciated. If it would also help I can post the video of it starting up so you can hear what I’m talking about.
Thanks a TON…I’m pulling my hair out dealing with this thing!
I’m running a GM 151 Iron Duke with a 2 barrel Rochester carb. I fired the engine up for the first time in a few months and it runs rough – very rough – and if I don’t continually give it gas it will stall. I contacted the PO who informed me that after he had the carb rebuilt and installed it had vacuum problems but “he’s not a mechanic and his friend knew enough to plug a few lines” to get it to start. He never drove it after the carb was installed and I bought it shortly thereafter.
My previous post mentioned a potential starter relay problem but essentially it could be anything…however seeing the SheetRock screws makes me uneasy, as does the charcoal canister not being hooked up.
So I’ve decided to run the current setup by you guys and see if you can help me out. If possible I’d like to hook the charcoal canister back up.
I labeled the picture here with some letters and numbers I hope you can follow:

In summary:
- “A” is plugged
- “B” comes from the fuel pump
- “C” is plugged
- I labeled the spindle looking thing ‘X’ because I have no idea what it is. It has 4 hose outlets – 2 on the top, 1 towards the front of the vehicle and 1 towards the rear of the vehicle. The 1’s are connected to each other and the 2’s are connected to each other.
- Not sure what ‘3’ is but the 3’s are connected

On the opposite side (the driver side) of the carb there’s a rigid hose that goes to the valve cover. The PCV valve on the valve cover is connected to the air cleaner assembly.
I pulled the charcoal canister and after some scrubbing found the 3 ports are labeled (from L to R) PCV, Fuel Tank, Carb Bowl.
So…what do you think goes where? And what should I do with the PCV port on the charcoal canister if the line is going to the air cleaner assembly?
Also here’s a picture looking down on the carb, taken from leaning over the passenger wheel:

Anything look fishy? I know it’s a bit of a long shot diagnosing these things virtually but any help is appreciated. If it would also help I can post the video of it starting up so you can hear what I’m talking about.
Thanks a TON…I’m pulling my hair out dealing with this thing!