'67 C20 Rochester 2G carb question

[Trevlar]

I purchased a 1967, 283, Chevy C20 Custom Camper about a month ago. The owner said that in order to drive the vehicle, you had to keep the manual choke out about 2/3 when taking off. I thought that I could get help and figure it out, but so far, I'm still struggling. Disclaimer: I am not an auto mechanic, but I am an engineer so I'm learning this as I go!

It idles fine, but when you press the accelerator (on takeoff) it will die out unless the choke is out about 2/3 as instructed. I rebuilt the carb with a quality kit and noticed that the housing for the accelerator pump did not have a port from the float bowl like it showed in all of the diagrams I had seen. I also saw a thread that said that you should see gas shoot into the carb when you manually stroked the accelerator with the engine off. I do not see the gas. That's when I took the carb back off and checked the accelerator pump again.

Can anyone look at these pics and tell me that I have the correct carb that is suppose to be on this truck and that I do not have to have the port from the float bowl that leads into the bottom of the accelerator pump housing?

Thanks!

[bowtiecharlie]

Well I looked up the number on the tag you had , and if it was all original that should be the correct carb for your vehical. It is a r2-2g.They used that carb on chevy and gmc's p/u's from 63 thru 67. As for your no gas upon accleration as you state,you could have a plugged acclerator port from your float-bowl area to the discharge area. That is under the 3 screw venturi port on the main body. Or most likely you are missing the 2 balls and maybe the spring on the acclerator port! Did you soak it in carb cleaner? Napa sells a 1 gallon can with a basket in it for this!! Make sure and blow out the ports!! Here's a really good link on you tube to help with your problem.

Rochester 2G, 2GC 2 Jet Carburetor Rebuild - Part...

This is part 1 the other parts are on you-tube for the entire rebuild!! .
Good Luck!!!
Chuck

[Trevlar]

Thank you for your reply. I had stumbled upon the videos that you had suggested and they did help me rebuild the carb with confidence.

Back to the accelerator pump for a second: if you look at the picture attached (red arrow), there is NOT a port leading from the float bowl to the bottom of the accelerator pump like I've seen in many other 2G carbs online. The rebuild kit even included the check ball for this port (goes under the accelerator pump, in the bottom), but I noticed that there was not a port to plug. Only the port leaving the accelerator pump is there. So as a test, I left the air horn off of the carb and filled the float bowl with gas. Using the accelerator pump with my hand, I plunged it down and gas did go to the top side of the venturi port, past the check valve with the spring. But as I released the pump to rise, it did not get any gas back to the underside of the piston, as it had no way to get it. There is a slot in the accel.pump housing (at approximate 10 o'clock in the picture), but the piston does not rise above it to get gas under the piston.

All of this might not matter, but I found it odd that this carb was that much different than all of the ones that I see online. I wondered if it was a carb from a 'six-pack' config?? Somewhere I read that only one of the three in that configuration used an accel.pump, but I have no idea if that is correct. I don't even know if the tag on the carb is from that carb, as it was under a screw and could have been switched.

Any suggestions or comments are welcomed!!!

[Wrenchbender Ret]

I think the gas goes in the slot & goes through the hole in the accelpump. I just did 3 of them building a tri-power & they did not have a check valve in the bottom of the well.

[Trevlar]

Originally Posted by Wrenchbender Ret

I think the gas goes in the slot & goes through the hole in the accelpump. I just did 3 of them building a tri-power & they did not have a check valve in the bottom of the well.

Well then that answers my question, thx. I'll put it back together and search in a different direction.

[Olive1970]

Did you still have the divider plate for the bowl/float that sits in next to the chamber for the accelerator pump?

[Trevlar]

Originally Posted by Olive1970

Did you still have the divider plate for the bowl/float that sits in next to the chamber for the accelerator pump?

Yes Sir. Aluminum, with approximately 3/16" triangle cut off one corner that sits against the bottom of float bowl, with the cut side aligned with the 'slot' in the accel.pump housing. That is the orientation that it was when I removed it...sound right?

[Olive1970]

Originally Posted by Trevlar

Yes Sir. Aluminum, with approximately 3/16" triangle cut off one corner that sits against the bottom of float bowl, with the cut side aligned with the 'slot' in the accel.pump housing. That is the orientation that it was when I removed it...sound right?

Sounds right to me bud. Just make sure you put it right back in when putting the carb back together...not like I have been there before

Did you end up replacing the pump too?

[luvbowties]

Originally Posted by Trevlar

Thank you for your reply. I had stumbled upon the videos that you had suggested and they did help me rebuild the carb with confidence.

Back to the accelerator pump for a second: if you look at the picture attached (red arrow), there is NOT a port leading from the float bowl to the bottom of the accelerator pump like I've seen in many other 2G carbs online. The rebuild kit even included the check ball for this port (goes under the accelerator pump, in the bottom), but I noticed that there was not a port to plug. Only the port leaving the accelerator pump is there. So as a test, I left the air horn off of the carb and filled the float bowl with gas. Using the accelerator pump with my hand, I plunged it down and gas did go to the top side of the venturi port, past the check valve with the spring. But as I released the pump to rise, it did not get any gas back to the underside of the piston, as it had no way to get it. There is a slot in the accel.pump housing (at approximate 10 o'clock in the picture), but the piston does not rise above it to get gas under the piston.

All of this might not matter, but I found it odd that this carb was that much different than all of the ones that I see online. I wondered if it was a carb from a 'six-pack' config?? Somewhere I read that only one of the three in that configuration used an accel.pump, but I have no idea if that is correct. I don't even know if the tag on the carb is from that carb, as it was under a screw and could have been switched.

Any suggestions or comments are welcomed!!!

..."but the piston does not rise above it to get gas under the piston"...

Sounds like linkage (pump-linkage?) assembled incorrectly, as piston MUST rise above bottom of slot to allow fuel to re-fill the pump-well. And do NOT install a ball in bottom of pump well.
On some of those carbs and/or kits you have to adjust the float higher than the instruction sheet calls for--quite touchy and may require several attempts.
HTH,
sam