Inspection - Tecumseh ECV105 Technician's Handbook

INSPECTION

After careful disassembly of the carburetor and the removal of all non metallic parts, the carburetor body and all other
metallic parts should be cleaned with solvent, or commercial carburetor cleaner, no longer than 30 minutes. Use compressed
air and soft tag wire to clean internal carburetor passages. To do a proper cleaning job, the welch plugs must be removed
to expose the drilled passages.
NOTE: The nylon check balls used in some diaphragm carburetors are not serviceable. Nylon can be damaged if
subjected to harsh cleaners for prolonged periods.
Throttle and Choke
Examine the throttle lever and shaft, choke lever and shaft, and carburetor body at the bearing points and holes into
which the linkage is fastened, and replace if worn or damaged. Any looseness in these areas can cause dirt to enter the
engine and cause premature wear. If dust seals are present, these should be positioned next to the carburetor body.
Idle and High Speed Mixture Adjusting Screw
Examine the idle mixture needle tip and tapered surface
for damage. The tip and tapered surface of the needle must
not show any wear or damage at all. If either is worn or
damaged, replace the adjusting needle. Tension is
maintained on the screw with a coil spring. Examine and
replace the "O" ring seal if damaged (diag. 40).
Examine the tapered surface of the high speed mixture
needle. If the tapered surface is damaged or shows wear,
replace the needle (non-emissioned). Some Tecumseh
carburetors use serviceable jet main nozzles. These are
identified as being non-metallic.
Fuel Bowl Retaining Nut
The retaining nut contains the transfer passage or metering
jet through which fuel is delivered to the high speed and
idle circuit of the carburetor. If a problem occurs with the
idle circuit, examine the small fuel passage in the annular groove in the retaining (metering) nut. This passage must be
clean for the proper transfer of fuel into the idle metering circuit. Torque retaining nut to 50 in. lbs. (5.65 Nm) when
reinstalling.
There are two different types of bowl nuts that are used on adjustable main, float style carburetors. One type has one fuel
metering port at the bottom of the nut, and the other has two fuel inlet ports at the bottom of the nut. This difference
relates to calibration changes to the carburetor and is dependent on the application (diag. 41).
NOTE: DO NOT INTERCHANGE BOWL NUTS.
The fuel inlet ports must be free of any debris to allow proper fuel flow.
Fuel Bowl, Float, Needle and Seat
The float bowl must be free of dirt and corrosion. Clean with solvent or carburetor cleaner.
Examine the float for damage. Check the float hinge bearing surfaces for wear, as well as the tab that contacts the inlet
needle. Replace any damaged or worn parts.
The needle and seat should be replaced if any fuel delivery problems are experienced (flooding or starvation). Sealing
problems with the inlet needle seat may not be visible, so replacement is recommended.
Diaphragms, Pulse Pumps, and Primer Bulbs
Inspect diaphragms, gaskets, and primer bulbs for cracks, tears, hardness or brittleness. Replace if necessary.
20
RETAINER NUT
"O" RING
BRASS WASHER (used to protect the
"O" ring from the spring)
SPRING
HIGH SPEED
ADJUSTMENT SCREW
IDLE FUEL
TRANSFER
FUEL-
PASSAGE
METERING
PORT
ONE-HOLE TYPE
40
FUEL-INLET
PORTS
TW0-HOLE TYPE
41