O.S. Carburetor 21J3-1 21XR-B Version II

Tower Stock# OSMG2401  •  Manufacturer Stock# 2AW81000
O.S. Carburetor 21J3-1 21XR-B Version II (large view)
Notes from our tech department:
This is the 21J3-1 Slide Valve Carburetor for the
21XR-B Version II 1/8 scale Buggy Engine, OSMG2056.


Aluminum body
Replaces worn or damaged carburetors


Assembled 21J3-1 Slide Valve Carburetor with Carburetor to Crankcase
O-Ring, key #5


Carburetor Settings, NOTE carburetor is preset at factory and
requires very small adjustments
Needle Valve: Run vehicle with throttle fully open a few times over
long straight course to observe vehicle speed. Close needle valve
15 and repeat run. Gradually close needle valve in subsequent
runs to achieve highest speed taking care not to close needle
valve too far and overheat engine.
Metering Needle: With engine running, close throttle and allow
engine to idle for about 5 seconds then fully reopen throttle.
Turn metering needle clockwise 15-30 to lean mixture if
excessive smoke is observed, or counterclockwise 15-30 to
richen mixture if engine speeds up momentarily and then cuts out


Does not include Reducers, order OSMG2498 for the 7mm Yellow Reducer,
or OSMG2471 for the 8mm Red Reducer.

jxs 10/02/17



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