MTD 1850 - Manual (Page 14)

Step 3. Place your foot on the rear of the depth bar
and apply pressure. The belts will go slack.
Step 4. Remove the REAR belt first and ALLOW IT TO
FORM A LOOP AROUND THE VARIABLE
SPEED PULLEY.
Step 5. Slide the center section of the variable-speed
pulley towards the engine. See Figure 4-7.
Step 6. Remove the FORWARD belt from the engine
pulley and the variable-speed pulley.
NOTE
By following this order of belt removal,
it is not necessary to remove the belt
guard on the varible-speed pulley.
Step 7. Remove the rear belt from the variable-speed
pulley.
Step 8. Reassemble with the new belts.
FIGURE 4-9. CARBURETOR ADJUSTMENT
4-n. ADJUSTING THE CARBURETOR
Minor carburetor adjustment may be required to
compensate for differences in fuel, temperature, alti­
tude and load.
To Adjust Carburetor:
Turn needle valve clockwise until it just closes. See
Figure 4-9.
CAUTION
Valve may be damaged by turning it in
too far.
Now open needle valve IV 2 turns counter-clockwise.
Close idle valve in same manner and open V a to %
turns. This initial adjustment will permit the engine to
be started and warmed up prior to final adjustment.
Final Adjustment;
Turn needle valve in until engine misses (lean mix­
ture) then turn it out past smooth operating point until
engine
runs unevenly (rich mixture). Now turn needle
valve to the mid-point between rich and lean so the en­
gine runs smoothly.
Hold throttle at idle position and set idle speed ad­
justing screw until fast idle is obtained (1750 RPM).
Hold throttle in idle position and turn idle valve in
(lean) and out (rich) until engine idles smoothly. Then
reset idle speed adjusting screw so that engine idles
at 1750 RPM. Release throttle—engine should accel­
erate without hesitation or sputtering. If engine does
not accelerate properly, the carburetor should be re­
adjusted to a slightly richer mixture.
4-12. ADJUSTING CARBURETOR CHOKE
Proper choke and stop switch operation is depend­
ent upon proper adjustment of remote controls on the
powered equipment.
To Check The Operation Of The Choke:
Step 1. Remove the air cleaner.
Step 2. Pull the throttle control all the way out to the
CHOKE position. See Figure 2-1. The choke
should be closed.
Step 3. The engine should shut off when the throttle
control is all the way in. (STOP position.)
To Adjust;
Place remote control lever on equipment in FAST
(high speed) position. Loosen control casing clamp
screw "B." Move control casing "A" and wire until lever
"D" touches choke operating link at "C." Tighten cas­
ing clamp screw "B." Replace air cleaner. See Figure
4-10.
4-4