2fst2c

iTrader: (114)

I know O.S. has a dozen different carbs for the .21's. They seem to go up in alphabetical order 21c-21? Can anyone tell me the difference between a 21H and a 21J carb? I see the 21H was used on the speed motors but now I'm seeing a 21J carb is out. Is the 21J the latest and greatest or ? Thanks.

shady3031

iTrader: (26)

I believe the newest is 21JS. Not sure what all the differences are

PTP Racing

iTrader: (2)

I think the only difference is the location of the idle screw.

2fst2c

iTrader: (114)

Thanks for the info. I looked at them both and the idle screws are in different locations and different design. The J is built in to the casting where the H is outside of it. Both should work equally as far as performance I would guess?

quicklosi

iTrader: (5)

as far as performance goes they both work identical i had both on my old speed. it is a tuning issue. with the 21H the idle screw is underneath so when you need to adjust your idle it is a pain in the @#$ to get a screwdriver in there. with the new 21J it is much easier to adjust the idle now that it is relocated up on the back side of the carb

2fst2c

iTrader: (114)

Thanks! That's what I wanted to know. I am going to get one to replace the carb on an Orion motor and wasn't sure if I should get the H or the J.