Carter Metering Jets 120D27

• Thread: 5/16 x 24
• Orifice: choose size from the drop down menu above

• AFB - rod and jet specs
• AVS - short jet. Some of the AVS carbs use the longer jet.
• Edelbrock
• BB - jet specs
• BBD - short jet. Some of the early BBD carbs used a long jet 1/2" or so, these are not available.
• WCD
• YF, YFA - jet specs
• YH
• WD-0 - no gasket needed
• WCFB - WCFB Jet Sizes
• Weber - jet sizes

Most AFB & AVS carburetors will have matching jets in the primary and then matching jets in the secondary. The Weber marine, 4 barrel is an exception to this. The jets can be a different size one each side of the carburetor.

ALTITUDE:
To compensate for higher altitude, change your jet .002 for over 5,000 feet. This is approximate because with the lousy fuel we have these days, the old ways of calculating sizes just aren't the same anymore. Using the testing method above is the best way to be sure.Carter used a 3 number system when marking jets. When the 1st number is 3, then the jet size is less than .100 inch. 365 would mean .065. When the 1st number is 4, then the jet size is .100 inch or more. 410 would mean .110.Jet sizes on the Carter carburetor can sometimes be hard if not impossible to read. In those cases use drill bits to measure the hole, then convert the drill bit to decimal.

NUMBERING
Some Carter jets use a 3 digit number to indicate the size. Example 630 would = .063 in our list.

JET TESTING
To determine if you have the correct jets in your carburetor, operate your vehicle for 20 minutes at sustained speeds. Stop and pull a plug.

• Gray - Good
• Black - move down one jet size
• White - move up one jet size

Do it all over again until you get a gray plug.