- Rochester 4 Jet Identification
- 4 Jet Troubleshooting
- Check Balls
- 4 Jet Flooding
- Jet Sizes
- Bogs When Stepping on the Gas
- Float Bowl Vent
- 4 Jet Power Circuit
Where to find the carburetor number:
Please do not distribute the manuals listed. Instead we would appreciate a link to this page. https://carburetor-parts.com/Rochester-4G-4GC_ep_349.html
Rochester 4G, 4GC Carburetor Manual
Free Rochester 4G, 4GC parts catalogs. One way to help identify your carburetor would be to match a part number from your carburetor (there is usually one somewhere), with a part in the catalog. Once you have done that, you have your carburetor number.
|1956 Buick Change in Primary Jets||7009200|
|1956-58 Chevrolet||7008737, 7009846, 7012126, 7012128, 7011108|
|1962 Buick Adjustment Specifications||7020040, 7020041|
|1962-65 Chevrolet V8 Truck w/Governor||7020025, 7020029|
|1963 Buick Special V8 215"||7023044, 7023045|
|1963-65 Buick V8 401"||7023040, 7023143, 7024040, 7025040,7025140|
|1964 Buick V8 300"||7024044, 7024045|
|1963-64 Oldsmobile||7023050, 7024154, 7024050|
|1965 Olds F-85 & Jetstar 88||7025054, 7025157, 7025158, 7025055|
|1965-67 Chevrolet V8 Truck 327||7025125, 7036125, 7027125, 7037125|
Rochester 4G Marine Carburetor
|Chris Craft Adjustments & Specifications||7013071, 7015090|
|Owens Adjustments & Specifications||7023184|
Rochester 4GC Jet Sizes
Buy your Rochester 4G, 4GC jets here. More Jet Sizes
|Carburetor Number||Primary Jet||Secondary Jet|
1956 Buick - Change in Primary Main Metering Jets. 4GC, carburetor number: 7009200 A change was made while being produced to this carburetor. The primary main jets were changed from .056 to .060. A "D" stamped on the carburetor tag signifies that this change was made.
Spring Loaded Floats - Torsion Spring
Some of the 4 Jet carburetors had a spring mounted on the float pin and hooked to the float. This helps take the bounce out of the float on rough roads. This is a part that is not being produced so what do we do now?
Watch a video about the accelerator pump vent.
Watch a video about rebuilding the Rochester 4 Jet.
Watch a video about the Rochester 4GC integral choke.
Watch a video about the Rochester 4G jets.
Watch a video about the throttle body gasket and looking for vacuum leaks.
Can one of the emulsion tubes be missing from the venturi? Answer: Sometimes those fall out. I would simply try to find another 4G and pirate an emulsion tube from its booster cluster. Compare the size/number/placement of holes with the remaining tube and modify as necessary. Install new tube to same depth as old one with a light coating of Permatex Anaerobic Gasket Maker on the press-fit surface. Question: When I took apart my 4gc (7024121) there was no aluminum check ball in the pump intake cavity. Does it take the large one or the small one that is in my kit?
1st you have to be sure you need a check ball. Carburetors that use a check ball in the accelerator pump well will have two holes at the bottom. One for intake and the other for out flow. When there is only one hole, then no check ball is needed since the hole is the out flow and if you placed a check ball there, the flow to the main discharge would be cut off. When you have two holes, then use the smaller of the check balls and these are often made of aluminum instead of stainless steel. Aluminum is used to make the check ball lighter since only the weight of the fuel lifts the check ball off of the hole to allow fuel to enter.
Needle & Seat
The 4 Jet uses 2 sets of needle & seats. Some 4 jets have different size needle & seat for the primary & secondary. When this happens use the bigger needle & seat on the primary side.