Carburetor Body

Install vent housing assembly (39), gasket (40), idle bleed tube (41), clamp (38), and screws (37). Start tube into holes first, then tap housing into place. Pull clamp (38) just tight enough so that outer ends of clamp touch body bosses.

Install drain plug and gasket (35) and high-speed fixed jet (34).

Position high-speed needle valve housing (30) in body, with needle valve (31), packing nut (32) and packing (33) assembled in housing.

When installing this set of parts in the main body, always back out the needle valve so the point will not enter the valve hole in the main body when the housing is pulled up tight. Pull up the packing nut just enough to prevent the needle valve from turning too freely.

Be very careful not to jam the needle valve into the seat hole, and deform the hole entrance.

Since the fixed jet supplies the main bulk of fuel to the nozzle and is supplemented by a maximum fixed amount from the high-speed needle valve, turning the needle valve completely off may, under certain conditions, cause the mixture delivered by the nozzle to be too lean. Turning the needle valve on three to four turns will cause the nozzle mixture to be definitely on the "rich" side but not excessively rich for normal conditions. As a rule, keep the high-speed needle valve setting as "lean" as possible, consistent with good performance. See "Adjusting Carburetor."

Assemble the nozzle (29) in place using an improvised screwdriver as described under "Carburetor Body Disassembly."

Model

Drill Size

DC-1, IL, 1M, 10, 6, 7, 12 DC-2

55 (.052) 70 (.028)

Turn the entire body upside down, drop in the idle tube (28), small end first, jiggle the body, and the tube will locate itself in the body hole. Do not bend, twist or damage the idle tube in any way. Press on plug end of tube until tube is seated and the bottom of the plug extends approximately 1/32 in. out of nozzle passage. When installing bowl nut (26) and gasket (27), spring tension will hold the idle tube firmly in place.

Assemble support bracket (25), nut and lock washer (24).

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