Remove carburetor from engine
Remove high speed adjusting needle, packing nut and packing (Scibe mark on body and bowl)
Remove bowl nut, gasket, and bowl
Remove float pin, float, needle & seat. Check float for dents, leaks and wear on float lip or float pin holes. If float is brass, submerge in hot water and look for bubbles to test for pin hole leaks
Remove bowl ring gasket
Low speet jet assembly installed permanently. DO NOT REMOVE
Remove idle adjustment screw and spring
Nozzle installed permanently. DO NOT REMOVE
Remove throttle valve screw, valve and shaft, and lever assembly
Do not remove choke valve and shaft unless replacement of these parts is necessary
Clean all parts with solvent, making sure all carbon accumulation is removed from bore, especially where throttle valve seats in casting. Clear passages with nylon brushes. Blow out all passages with compressed air. Replace all worn or damaged parts. Always use new gaskets.
Install throttle shaft and valve. Valve must be installed with trademark “C” on side toward idle port when viewing from flange side. Always use new screws and peen in place to prevent loss. With valve screws loose, seat valve by tapping lightly with small screwdriver. Hold in place while tightening screws.
Install needle seat, needle, float, and float pin.
Set float level with carburetor casting inverted, float resting lightly against needle in its seat. There should be 11/64” clearance between outer edge of casting a free end of float (side opposite needle & seat). Adjust by bending lip of float.
Install high speed needle, packing nut and packing in bowl. Turn needle in until one thread on needle is visible at packing nut. Then install bowl ring gasket, bowl (line up scribe marks), bowl nut gasket and bowl nut. Tighten securely.
Turn high speed needle in until it just seats in body, then back out 3/4 turn.
Install idle adjusting screw, finger tight. Back out approximately 3/4 turn. Do not use pliers or screwdriver as it may damage idle screw.
Install carburetor on engine and make idle and high speed adjustment as necessary.
After rebuilding and installation on engine is complete, the high speed and idle screw adjustments must be made.
With the high speed needle turned counter clockwise (from closed position) 3/4 turn and idle screw turned 3/4 turns open, start engine.
With the engine at normal operating temperature, accelerator engine and check response. The high speed needle should be adjusted for the leanest possible mixture which will allow satisfactory acceleration. If the engine misses and backfires, the high speed mixture is too lean and the high speed adjustment needle must be turned counter clockwise 1/10 turn at a time to correct this condition. If the engine leads (heavy exhaust) and is sluggish, the mixture is too righ and the high speed adjustment needle must be turned clockwise 1/10 turn at a time to correct.
To make final check of the high speed adjustment, operate the engine under load and adjust.
The idle screw should be adjusted intermittently while making the high speed adjustment. DO NOT USE FORCE ON THE HIGH SPEED NEEDLE OR IDLE SCREW AS DAMAGE MAY RESULT.