Dura Force Carburetor Kit

Transcription

1 SERVICE BULLETIN LAWN-BOY PRODUCTS WALK MOWER #38 September 25, 2006 Dura Force Carburetor Kit PRODUCT: Walk Behind Mowers UNITS AFFECTED: Model Numbers: Serial Numbers: C (Int l) C (Int l) (Int l) (Int l) (Int l) SUBJECT: SITUATION: Carburetor assemblies have been replaced by a carburetor kit. Complete carburetor assemblies for the Dura Force engine are no longer available. If you order the complete carburetor you will receive a kit containing all of the individual components. Detailed repair instructions for carburetor assembly can be found in the E Engine Service Manual, form # A copy of the manual instructions are attached. Note: Exceeding specified torque value on the jets or screws can damage the carburetor body. Svc Mgr Tech 1 Tech 2 Tech 3 Tech 4 Tech 5 Parts Mgr Sales Mgr Warranty Mgr Initials

2 LAWN-BOY PRODUCTS WALK MOWER #38 ( ) Page 2 WARRANTY: PARTS: Does not apply; information only Carburetor Kit

3 ASSEMBLY Important: Over-tightening the jets or main nozzle can damage the carburetor body. 3. Apply one drop of Loctite 242 blue to the threads, and install the pilot jet (Fig 02). Torque to in-lbs. ( Nm). 1. Install the high speed jet into the fuel nozzle. Torque to 4-6 in-lbs. ( Nm). 2. If the nozzle has been removed, turn the carburetor over. Apply one drop of Loctite 242 blue or equivalent to the nozzle threads, and install the nozzle assembly into the carburetor body (Fig. 01). Torque to in-lbs. ( Nm). Fig Apply one drop of Loctite 242 or equivalent to the seat threads, and install a new brass inlet fuel valve seat (Fig. 03). Torque to in-lbs. ( Nm). Fig Fig

4 5. Install a new inlet valve needle and clip on the fl oat. 6. Install the fl oat assembly with a new fl oat hinge pin in the bottom of the carburetor. Ensure that the hinge pin is positioned properly to keep the fl oat level. The fl oat should be free to move up and down easily in the carburetor body. 7. Adjust fl oat so height is 1/2 ±.03 (.76 mm) from bowl fl ange (gasket not in place) to top of fl oat (Fig. 04). 8. Pressure check carburetor. Attach pump with pressure gauge to fuel inlet fi tting on carburetor (Fig. 05). With carburetor upside down (fl oat up), raise fl oat and lower to its normal position. Pump pressure to 5 psi (.35kg/cm). It should hold this pressure indefi nitely. For practical purposes, test for 10 or 15 seconds. If it does not hold, wet the needle and seat, and repeat the test. Fig Fig Install the fuel fi lter over the fuel nozzle (Fig. 06). Fig

5 10. Install a new fuel bowl gasket and the fuel bowl with the four bowl retaining screws (Fig. 07). Torque to in-lbs. 12. Place the collar and spring over the carburetor fi tting (DuraForce engines) (Fig. 09). Fig Fig Hook the governor spring into the bottom of the governor collar (DuraForce engines) (Fig. 08). 13. Install the air vane and throttle shaft into the carburetor body by very carefully pushing the shaft through the collar into the carburetor body. (Fig. 09). 14. Push the throttle plate into the throttle shaft. (The plate only inserts one way.) If the throttle plate does not fi t snugly, replace the throttle shaft. The governor spring can now be attached to the throttle shaft. Note: Be sure air vane operates smoothly and does not stick or bind. Fig

6 INSTALLATION 1. DuraForce - Assemble the carburetor, gaskets, heat shield, and air fi lter box. Use the two mounting screws to hold the parts together during assembly. 2. DuraForce engines - Guide the air vane through the opening in the shroud base from the bottom of the base, and attach the carburetor to the engine with two mounting screws. Tighten them to specifi cations. 3. DuraForce engines - Insert the bent wire of the throttle cable into the vertical tab of the speed control lever. Set the throttle to fast and the speed control lever so that the throttle plate is in the full open position. The cable is adjusted at the cable clamp on top of the air fi lter box. 4. Install the fuel line and primer tube on the appropriate carburetor fi ttings. 5. Check that the choke and air vane assembly move freely and is properly adjusted. If the air vane requires adjusting, see Presetting the Governor on page Install the air fi lter element and cover. 4