McCulloch MT705 manual Spark Arrestor Maintenance, Carburetor Adjustment, Check Fuel Mixture

MAINTENANCE AND REPAIR INSTRUCTIONS

SPARK ARRESTOR MAINTENANCE

NOTE: The exhaust can only flow in one direction: AWAY

from the engine. Pay close attention when disassembling the muffler so you can put it back together correctly. Failure to do so will damage the unit and may cause serious personal injury.

1.Remove air filter/muffler cover. Refer to Removing the Air Filter/Muffler Cover.

2.Locate the muffler, but do not remove it. Find the two

(2) screws on the bottom of the muffler (Fig. 28). These two screws hold the Spark Arrestor Hood Assembly and the spark arrestor screen to the bottom of the muffler. Remove the two (2) screws using either a torx #20 or flat blade screwdriver.

3.Using a small flat blade screwdriver, carefully pry up the spark arrestor screen from the recessed hole, taking care to notice that the “raised” part of the spark arrestor screen is inside the recessed hole. Remove the spark arrestor screen from the muffler.

4.Clean the spark arrestor screen with a wire brush. Replace it if it is damaged, or if you are unable to clean it thoroughly.

5.Reinstall the spark arrestor screen by putting the “raised” portion of the screen inside the recessed hole of the muffler. Make sure that the spark arrestor screen fits flat against the muffler.

6.Place the spark arrestor plate on top of the spark arrestor with the “raised” side up and the opening facing towards the engine (Fig. 28).

7.Place the spark arrestor hood on top of the spark arrestor plate with the “raised” side up and the opening facing AWAY from the engine (Fig. 28). Verify that the exhaust will be directed AWAY from the engine.

Muffler

Spark Arrestor

Screen

Spark Arrestor

Plate

Opening

Engine

Recessed Hole

Spark Arrestor Hood

Assembly Includes:
Spark Arrestor Plate	Spark Arrestor
Spark Arrestor Hood
	Hood
and Screws
	Screws
	Fig. 28

8.Replace the two screws you removed in Step 2 and tighten them securely.

9.Reinstall the air filter/muffler cover.

WARNING: If the exhaust deflector assembly is

not tightened securely, it could fall off causing damage to the unit and possible serious personal injury.

CARBURETOR ADJUSTMENT

The idle speed of the engine is adjustable through the air filter/muffler cover (Fig. 29).

NOTE: Careless adjustments can seriously damage your unit. An authorized service dealer should make carburetor adjustments.

Check Fuel Mixture

Old and/or improperly mixed fuel is usually the reason for improper unit performance. Drain and refill the tank with fresh, properly-mixed fuel prior to making any adjustments. Refer to Oil and Fuel Information.

Clean Air Filter

The condition of the air filter is important to the operation of the unit. A dirty air filter will restrict air flow and change the air/fuel mixture. This is often mistaken for an out of adjustment carburetor. Check the condition of the air filter before adjusting the idle speed screw. Refer to Air Filter Maintenance.

Adjust Idle Speed Screw

If, after checking the fuel mixture and cleaning the air filter, the engine still will not idle, adjust the idle speed screw as follows:

1.Start the engine and let it run at a high idle for a minute to warm up. Refer to Starting/Stopping Instructions.

WARNING: The cutting attachment may spin

during idle speed adjustments. Wear protective clothing and observe all safety instructions to prevent serious personal injury.

Idle Speed Screw

Fig. 29

15