Carburetor Assembly - Tecumseh TM SERIES Technician's Handbook

CARBURETOR ASSEMBLY

1. Install new inlet screen(s) using a small flat punch
slightly smaller than the screen. Push in until the
screen contacts the seat.
2. If removed, install the high speed jet. Use a slightly
larger flat punch to install the brass welch plug over
the high speed jet. The closed, tapered end of the
plug goes toward the jet. Tap the brass welch plug in
until it is flush with the carburetor body. Apply sealant
like fingernail polish to the brass plug.
3. Install new welch plug(s) using a flat punch equal to
or slightly larger than the plug. The welch plug(s)
must be flattened by taps with a small hammer on the
installing punch. Sealant such as fingernail polish is
recommended to apply to an installed welch plug.
Use sparingly and wipe off excess immediately
(diag. 3-13).
4. Install the inlet needle, spring, metering lever and pin.
The metering lever hooks on the inlet needle and
rests on the metering spring. Install as an assembly
and install the retaining screw (diag. 3-14).
5. Check the metering lever tip height using a metering
lever gauge (part # 670325). The tip height should be
.060" to .070" (1.52 mm to 1.77 mm) from the face of
the carburetor body on Walbro carburetors. On
Tecumseh and Tillotson carburetors the tip of the
metering lever should be flush with surface of the
carburetor body.
6. Install the idle mixture screw and spring and back the
screw out from the closed position 1 - 1-1/8 turns for
Walbro, 1-1/4 - 1-3/8 turns for Tillotson carburetors.
7. Install the metering diaphragm, cover gasket, and
cover. Place the cover gasket (over the locator pins
on Walbro only) on the carburetor body, add the
metering diaphragm with the long rivet head toward
the carburetor body on top of the gasket, add the
cover and fasten the four screws (diag. 3-15).
Do not re-use old choke or throttle plate shutter screws.
New screws are treated with a dry Loctite adhesive to
secure them in place.
8. Install the pump gasket over the locator pins on the
pump cover, add the pump diaphragm next, and
place the assembly on the carburetor body. Check to
see that the locator pins fit the corresponding holes in
the carburetor body. Install the pump cover retaining
screw (diag. 3-15).
9. If removed on Walbro carburetors, install a new fuel
inlet fitting in the same position as the original (diag.
3-15). When installing a new fitting, insert the tip into
the carburetor body, then coat the exposed portion of
the shank with Loctite grade A (red), then press it in
squarely using support on the opposite side to
prevent damage to the carburetor body or fitting.
Press it in until the fitting bottoms out in the carburetor
body.
NOTE
Flat End
New Welch
Plug
Inlet Needle
Metering Pin
Metering Lever Tip
1. Metering Diaphragm Cover
2. Diaphragm
3. Diaphragm Gasket
4. Pump Diaphragm
5. Pump Cover Gasket
6. Pump Cover
4
5
6
Note: Punch should be of the
same or larger diameter than
the welch plug.
Carburetor Face
1
2
3
3-13
3-14
3-15
21