Emissionized Diaphragm Carburetion; Outboard Carburetors - Tecumseh AH520 Technician's Handbook

Loosen screw until it just clears
throttle lever, then turn screw in 1
IDLE SPEED ADJUSTMENT SCREW
turn.
THROTTLE SHAFT LEVER AND
Place detent reference mark to
RETURN SPRING
proper location. See chapter
appropriate to specific carburetor.
THROTTLE SHUTTER
IDLE,
Remove welch plug and blow air
INTERMEDIATE
through air passages.
AND AIR BLEED
ORIFICES
CHOKE SHAFT AND LEVER
Check shaft for binding. Position
shutter opening towards inlet fitting
CHOKE SHUTTER
side of air horn.
*INLET SEAT Remove and replace.
GASKET
*INLET Primer bulb models have a Teflon
FITTING one way valve, in or behind the fitting.
*INLET
NEEDLE
Proper installation of assembly is
SEAT AND
important. See appropriate chapter
SPRING
for procedures.
ASSEMBLY
*DIAPHRAGM
Gasket and diaphragm sequence
GASKET
may be reversed on some models.
Head of rivet must touch inlet needle.
*DIAPHRAGM
Hole must be clean. On models with
primer bulb, vent hole is very small
ATMOSPHERIC VENT HOLE
and is located off center or in the
primer bulb.