I had a carb rebuilt for a friend and it seems to be "surging", like it is lean. The carb came out of a box of carbs, so I have no idea what it came off of. I thought that maybe it originally came off of a 170 and had different jets, so I explored that idea. To my surprise, I opened 4 carbs and found 4 different jet & metering rod sizes. I had no idea that there would be so many! I can't accurately measure the jet size so I have listed the part number on the jet. Here is what I found with some additional data from the Internet:

Jet #, Rod Diam.
120-293S, .023 (1968-1969?)
120-263S, .025 & .035 (stepped) (listed as standard for 1963 on Carter doc.)
120-212S, .031 & .035 (stepped) (listed as one size lean for 1960 318)
120-429S, .041 & .045 (stepped) (in the carb. I had rebuilt, can't find more data)

Does anyone have an idea what I should be using for a 225 at sea level?

Thanks,

Update: I swapped in the 120-263S setup and I like it much better.

_________________
Chuck Rivers, Webmaster

What year car? What year engine?

Working on a 1964 Dart, 225, stock as far as I know (except for the carb). I measured the hole in the main jet @ .040 (.041 doesn't fit, so that should be accurate), and I don't see anything like that in the charts, or any listings that show the hole size for each jet number. I don't have enough different drill sizes to measure all the different jets.

_________________
Chuck Rivers, Webmaster

Just a quick response, may be revised later. Found a sheet for 65 dart that shows jet 120-263, 400-408 cc as standard for 225. Jet 120-267, 380-386 cc as 1 size lean. BBS carbs are air bleed, high float level, higher fuel level covers up the air bleed holes in main well, richer. Low float, low fuel level uncovers air bleed holes ,more air, less fuel, leaner. The level of fuel in main well goes up and down depending on air flow in venturi, engine load. Use same metering rods, lower float 1/32 [i have gone as much as 5/16 ] jet 120-293, 2 sizes richer. You got that one, maybe too rich, so lower float at same time. Another thing is the step up spring, longer and stiffer drives better, stages early and harder. At first go stiffer, change out later. With today's gas, worth a try.

Thanks matv91. They really didn't make this stuff easy. I've never had to mess with the Carters before.

_________________
Chuck Rivers, Webmaster

After market replacement carbs

Does anyone have more data on the jet sizes and step-up rods? I am trying to rebuild another old Carter and want to get it close enough so that I don't have to try 9 different combinations! I have already used the 120-263S jet & rod with the last rebuild, so I have the other 3 to chose from. I haven't found anything that mentions the jet sizes and the rods that were used with them.

_________________
Chuck Rivers, Webmaster