Rochester 2 Barrel - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jeffh · 07-10-2020, 06:30 PM

Tryed to fire up the 60 the other day. Prime the carb with a little gas it would run out the gas but no more. Thought well the float stuck/accelerator pump shot, time to put a kit in it. Bought a kit, took it off, was taking the idle screws out and this is what I came up with. Its corroded/eaten into the idle screw threads as you can see at the point of the screwdriver. More so on the right but a tiny hole you can see at the one on the left. I assume the base is garbage? Along with at least the one idle screw? Would any Rochester base work? I don't seem to have one laying around here so don't want to have one sent in to me then be just a little bit different and not work. Actually the motor/carb is from a 67 1 ton carb number 7027105. Any other things I should be aware of in putting a kit in this? Been awhile since I've worked on one and have had varying success with them in the past.

**Steeveedee** · 07-10-2020, 07:49 PM

This appears (especially since you mentioned the year) to be a carburetor for a manifold with the heat crossover port. Looking at those idle mixture screws, I'd personally try to find another carburetor. There's no way those screws are going to be efficient at adjusting the idle mixture. You might be able to contact one of the carburetor people who advertise here and get the parts you need, or send them the carb. I know that they aren't that hard to rebuild, it's just a thought. Potentially you could just braze that hole shut, but what do the idle screw seats look like?

Jeffh · 07-10-2020, 08:31 PM

What would be the purpose of a heat crossover port? And what makes whatever is in it so corrosive? One of the carb studs had totally rotted through and the one on the other side was very thin. I am hoping to get just a base rather than a complete other carb.

**cwcarpenter98** · 07-10-2020, 11:04 PM

The heat crossover sent exhaust gases through the manifold and that passage in the base of the carb to warm up the choke. On my 63, I had that same setup, and when I pulled the carb off, one of the studs broke off and everything in the passage was crusty. My choke never worked right because the crossover port was completely clogged on both sides of the intake manifold

**Steeveedee** · 07-11-2020, 11:15 AM

Yeah, that clogging was a common problem. I replaced a lot of those carburetors when I worked as a mechanic.

07-10-2020, 06:30 PM	#1
Jeffh Registered User Join Date: Sep 2017 Location: Red Oak Iowa Posts: 225	Rochester 2 Barrel Tryed to fire up the 60 the other day. Prime the carb with a little gas it would run out the gas but no more. Thought well the float stuck/accelerator pump shot, time to put a kit in it. Bought a kit, took it off, was taking the idle screws out and this is what I came up with. Its corroded/eaten into the idle screw threads as you can see at the point of the screwdriver. More so on the right but a tiny hole you can see at the one on the left. I assume the base is garbage? Along with at least the one idle screw? Would any Rochester base work? I don't seem to have one laying around here so don't want to have one sent in to me then be just a little bit different and not work. Actually the motor/carb is from a 67 1 ton carb number 7027105. Any other things I should be aware of in putting a kit in this? Been awhile since I've worked on one and have had varying success with them in the past. Attached Images

07-10-2020, 07:49 PM	#2
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,751	Re: Rochester 2 Barrel This appears (especially since you mentioned the year) to be a carburetor for a manifold with the heat crossover port. Looking at those idle mixture screws, I'd personally try to find another carburetor. There's no way those screws are going to be efficient at adjusting the idle mixture. You might be able to contact one of the carburetor people who advertise here and get the parts you need, or send them the carb. I know that they aren't that hard to rebuild, it's just a thought. Potentially you could just braze that hole shut, but what do the idle screw seats look like? __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

07-10-2020, 08:31 PM	#3
Jeffh Registered User Join Date: Sep 2017 Location: Red Oak Iowa Posts: 225	Re: Rochester 2 Barrel What would be the purpose of a heat crossover port? And what makes whatever is in it so corrosive? One of the carb studs had totally rotted through and the one on the other side was very thin. I am hoping to get just a base rather than a complete other carb.

07-10-2020, 11:04 PM	#4
cwcarpenter98 Senior Member Join Date: Jan 2018 Location: Hickory Flat, GA Posts: 4,494	Re: Rochester 2 Barrel The heat crossover sent exhaust gases through the manifold and that passage in the base of the carb to warm up the choke. On my 63, I had that same setup, and when I pulled the carb off, one of the studs broke off and everything in the passage was crusty. My choke never worked right because the crossover port was completely clogged on both sides of the intake manifold __________________ Christian Carpenter 1963 C10 - Frankentruck 283, Muncie 3 speed with overdrive Overdrive wiring here 1963-ish truck bed trailer - Half-Wit 1981 C10 - Penny 305, th350 --> Soon to be 350, Saginaw 4 speed 1995 Dodge Dakota Sport "I'll put it simple: if you're going hard enough left, you'll find yourself turning right." - Doc Hudson

07-11-2020, 11:15 AM	#5
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,751	Re: Rochester 2 Barrel Yeah, that clogging was a common problem. I replaced a lot of those carburetors when I worked as a mechanic. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

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