rochester 2GC no power valve

[Woody70]

I started disassembly on my rochester 2GC
And found no power valve I don't see any threads just a hole where it should be.
Does the marine application use one?

Boat info

carburetor number 7020993

Engine 120hp mercruiser I/O
serial number
2362287

Thanks
Woody70

 

[Don S]

Re: rochester 2GC no power valve

Of course the marine version has one. Obviously the last one into that carb missed something.

 

[Woody70]

Re: rochester 2GC no power valve

I don't see any threads for it to screw into

 

[Don S]

Re: rochester 2GC no power valve

I looked through manual #1, and it shows the power valve, and it shows that carb number (7020993). Also looked at the parts program that I don't put much faith in as far as pictures go, and it doesn't show one. On later models it does. but none of them show the pin and spring in the top of the carb that contacts the pin in the power valve. Do you have that pin and spring in the upper part of the carb?

 

[Woody70]

Re: rochester 2GC no power valve

Thanks for your help.
The only thing that was attached to the top part of the carb was the accelerator pump.

 

[Don S]

Re: rochester 2GC no power valve

Guess the old ones didn't use them.

 

[thumpar]

Re: rochester 2GC no power valve

My 1983 with Rochester 2gc had it.

 

[Don S]

Re: rochester 2GC no power valve

My 1983 with Rochester 2gc had it.

Do you have carb number 7020993 like he does?

 

[thumpar]

Re: rochester 2GC no power valve

Do you have carb number 7020993 like he does?

That is something I would have to look at tomorrow. With the weather on this side of the mountains we put the boat back in the garage and is hard to get to. I do know that it is original to the boat.

 

[Woody70]

Re: rochester 2GC no power valve

Ok thanks
I'll finish the rebuild and see how it goes.

 

[mikehoncho1123]

Re: rochester 2GC no power valve

Woody, I have mine torn apart and noticed the same (no power valve or piston). How'd your rebuild go without those parts? Carb #7028086.

 

[Woody70]

Re: rochester 2GC no power valve

When you say piston are you talking about the accelerator pump or the pin and spring?
If the hole that power valve goes in to is not threaded than I would think it's not needed.
As far as mine the rebuild went fine with no problems.

 

[mikehoncho1123]

Re: rochester 2GC no power valve

Looked exactly like your pictures. No threads in power valve hole and no pin and spring.

Update from Mike's carb parts: "That would be typical of a carburetor that was on a 3 deuce setup. The 2 end carburetors were like that. Not likely a marine carburetor."

Is this thing still usable as the only carb on my mercruiser 120 or should I get a new one? I pulled it to rebuild because it's lacking top end power.

 

[Woody70]

Re: rochester 2GC no power valve

I was thinking about getting a used carb from a wrecking yard and rebuilding it if this one has any performance problems after i get it in the water.
This was my dads old boat and I'm trying to get it up and running again.

 

[fishrdan]

Re: rochester 2GC no power valve

What type of wrecking yard? Boat wrecking yard I hope... You may find a similar automotive carb, but it's not going to be setup for "marine" applications, exterior and guts different.

 

[Thunderchicken68]

Re: rochester 2GC no power valve

I just started a rebuild on my 2G. Same number: 7020993.
No power valve. I will call mike in the morning, and pick his brain, but my guess is that this is correct. I'm having a bit of trouble getting my mind around the physics of it, but that is a kiekhaefer number. That would make it correct on my '68 Merc 120.

 

[Thunderchicken68]

Re: rochester 2GC no power valve

My rebuild is complete, and running great. The carb had no power valve, or stem. It also did not have a ball or return spring under the accelerator pump. I talked with Mike again, and he had never seen one like this. I also spoke with Walter at Go2Marine.com about it while I was ordering a new manifold. He has all of the old microfiche from merc, and the exploded view confirmed that they should not have the valve. There were also some 703XXXX models that were put together this way. The earlier comment about the Tri-Power, or "three Duece" applications, is close but no cigar. They also did not have any choke on carbs 1 & 3. The outside carbs work like secondaries on a 4Bbl.

 

[region4]

Re: rochester 2GC no power valve

According to the Service Manual (C-90-68648), the Mercruiser 120 does not have a power valve.

My rebuild is complete, and running great. The carb had no power valve, or stem. It also did not have a ball or return spring under the accelerator pump. I talked with Mike again, and he had never seen one like this. I also spoke with Walter at Go2Marine.com about it while I was ordering a new manifold. He has all of the old microfiche from merc, and the exploded view confirmed that they should not have the valve. There were also some 703XXXX models that were put together this way. The earlier comment about the Tri-Power, or "three Duece" applications, is close but no cigar. They also did not have any choke on carbs 1 & 3. The outside carbs work like secondaries on a 4Bbl.