F-12/F-14 carb info

Well its been well over a year since I"ve posted anything on the forum and about as long since I"ve been working on my F-12. Wanted to share something I discovered while tearing apart multiple F-12 and F-14 carbs.

I have two factory high compression gas carbs #29953-DC and two low compression kerosene special #29954-DB. The two main differences I found are in the Venturi and the Adjusting Screw Seat for the Fuel Adjusting Screw.

I can take pictures and measurements of the Venturi if anyone would like. The opening of the gas venturi is a lot larger than the kerosene one. It would be easy to drill out a kerosene one to the same factory specs as a gas one.

The Adjusting Screw Seat on both carbs have two holes. One being straight through the end. The other being through the side just above the threads. On the high compression gas carb both holes are drilled with a #49/.073" bit. On the low compression kerosene carb the holes are different sizes. The one out the end is drilled with a #56/.046" bit and the side hole is a #29/.136" bit.

Hope someone finds this info useful and may want to experiment with modifying their carb to see if any differences in power are found

I would think the holes would be bigger for the Kerosene carbs than the gas carbs.

John is spot on. Different jet size for Kero/distillate vs. gasoline. The Kero/distillate jet will run gasoline fine. However, it doesn't work so well the other way around. Since I will presume that you are going to run gasoline, don't sweat it.