Adjustment and Disassembly of Gasoline Motor NOTE: Additional spark plug fouling and heavier deposits in the engine combustion chamber and muffler may occur when older types or heavier SAE grades of Oil, engine (USA Spec. 2-104B) are used, and particularly if the oil and gasoline have not been thoroughly mixed. (See Par. 5D.) Misfiring, hard starting, and reduction in engine power are indications that spark plugs may need cleaning, regapping or replacement and that deposits must be removed. General Description This Mercury Engine is a single cylinder, two cycle, full anti-friction bearing type. Ignition is furnished by a high-tension Magneto, gear driven from crankshaft. Speed of engine is controlled by a gear driven. governor. Governor is set at the factory to limit speed of engine to 1500 R.P.M. This setting should not be disturbed. The carburetor intake air is washed by an oil bath air cleaner attached to the gasoline tank. Carburetor Adjustment (Refer to illustration "Bottom View of Motor.") The carburetor is properly adjusted before unit leaves the factory and any further adjustments should not be necessary except with temperature extremes. In the event carburetor (SKA-3100A) does require adjustment proceed as follows: Warm up engine thoroughly and if it stutters consistently under load, the mixture is too rich. Turn adjustment screw (SKA3023) to the right or clockwise until engine fires evenly. If the engine falters, skips, or loses power under load, the mixture is too lean and the adjustment screw should be turned to the left or counterclockwise until engine fires evenly. Be sure packing gland nut (SKA-3020) is tight enough to prevent adjustment screw from turning under engine vibration. Magneto Adjustments (Refer to illustrations "Magneto Assembly SKA-5100A" and "KB3Ğ Magneto") The magneto on the KB3G Engine is carefully engineered to provide quick, easy starting and maximum dependability of operation without adjustment or service. Field adjustment is rarely necessary and should not be undertaken except in strict accordance with instructions. The ignition spark may be tested in the following manner: remove magneto cover plate, remove ignition cable from magneto end cap (SKA-5102) socket, insert a short piece of stiff wire in socket and bend wire to within " of engine. Turn motor over at normal cranking speed. If a strong spark occurs, it is recommended that ignition cable, terminals, and spark plug be thoroughly inspected .before dismantling magneto. If no spark is observed under above test, remove magneto end cap (SKA-5102) by removing four screws (SKA-5105), and examine contact points (SKA5032A.) If points are badly pitted, replace them. Remove two SKA-5027 screws, remove breaker arm snap ring (SKA-5039) and washer (SKA5040). Both contact points can now be removed. After installing new points, adjust them to .012 to .015 inch gap by turning adjustment screw (SKA-5030). Lock breaker plate by tightening lock screw (SKA-5027). Be sure end cap gasket (SKA-5021) is intact before replacing cap. Try magneto for spark. If no spark or a weak reddish spark occurs, remove end cap and replace condenser (SKA-5047) with a new one. If magneto still will not show a spark, the coil is probably defective. Replace coil as shown under heading "Magneto Disassembly." Do not attempt to remove the magnetic rotor (SKA-5101) from housing. This should only be done by factory trained servicemen. It is recommended that the magneto assembly be returned to the factory for general overhaul or replacement of parts other than described above. Governor Adjustments (Refer to illustration "Right Side View of Motor") The governor (SKA-4100A) is adjusted at the factory to maintain the engine speed at 1500 R.P.M. If for any reason the governor should become out of adjustment, it can be reset as follows: turn adjustment screw (SKA-4105) clockwise to increase speed, and counter clockwise to decrease. Tighten locknut securely. Sensitivity of governor action is controlled by screw (SKA-4028). Turning this screw in (up) will increase sensitivity and turning it down (out) decreases sensitivity. Disassembly of Engine (Refer to all illustrations of Motor and Parts) Remove muffler (SKC-1921A) by removing two nuts (SKA-1552). Remove cylinder cover (SKB-1835) by removing six screws (SKA-1635). Exhaust manifold (SKA-1865) can now be slid off studs (SKA-1903). Remove magneto cover (SKA-1496) by removing four screws (SKA1662). Remove spark plug cover (SKA-1862) by removing two screws (A-919). To remove fuel tank, disconnect fuel line (SKA-1902A) by removing two gland nuts (SKA-1665), from carburetor (SKA-3100A) and shut-off cock (SKA-1666A). Remove following screws: one (SKA-1658) on top under spark plug cover, one (SKA-1658) on fan housing and one (SKA1901) on crankcase. Tank may now be lifted from engine. To remove fan hub assembly, remove fan screen (SKC-1542) which is attached to fan housing (SKD-1454XG) with a snap ring arrangement similar to a modern automobile hub cap. Pull fan and hub assembly (SKA-1457A) with fan hub puller (SKA-1788) as follows: Remove fan hub nut (SKA-1651) with a 5%" socket wrench. Insert puller into center of fan hub which is threaded for this purpose. Turn puller very tight and strike with light metal hammer once or twice, retighten puller and strike again. Repeat this procedure until fan assembly can be easily removed. Use discretion tapping on puller so as not to damage crankshaft or crankshaft ball bearings. When installing new cooling fan (SKB-1457) on fan hub (SKB-1455DXA), be sure and have 1/16" timing hole in correct relation to keyway. To remove fan housing, unscrew choke knob (A-1077) from choke rod. Remove two cap screws (SKA-1659). Fan housing may now be removed. To remove cylinder, remove four cylinder fastening screws (SKA-1535) and washers (SKA-1655) from stud in crankcase at base of cylinder. The cylinder may now be pulled up from studs and piston. To remove piston, take out piston pin lock rings (SKA-1473) from each end of piston pin (SKA-1468). It may be necessary to tap the pins out of the piston. If so, hold piston in such a way as not to bend the connecting rod by the force of the blow. Use a light hammer. To remove connecting rod, take out connecting rod bolts (SKA-1653) to remove cap. The rod is equipped with 28 needle type frictionless bearings (SKA-1654), which through necessity are installed individually. Be sure all 28 in rod are accounted for before proceeding further. After removal from crank shaft (SKC-1494), be sure to replace cap on rod in the same position is was originally. This is important as these parts are accurately machined to match perfectly. Use a heavy grease to stick rollers in place when reassembling. To remove crank shaft, remove mounting foot (SKB-1817) by removing two screws (SKA-1896) and one screw (SKA-1928). Remove combination drive and starter pulley (SKB-1909) by removing screw (SKA-1650) and applying puller. Remove two nuts (SKA-1555) from bearing housing studs (SKA-1160). Bearing housing assembly (SKD1522A) can now be slid off crank shaft. Crank shaft can now be removed by pressing out of crank case. To remove governor, remove four governor body screws (SKA-4106). Governor housing assembly (SKA-4100A-1) can now be removed. Remove two screws (SKA-1581) from governor flange. Governor flange assembly can now be removed from crank case. When reassembling be sure to have governor gasket (SKA-1652) and governor housing gasket (SKA-4102) intact. Governor gear should have a back lash of about .003 to .006 with crank shaft gear. To disassemble magneto (SKA-5100A) remove from crank case as follows: remove lock wire from the two locking screws (SKA-1615), remove the two screws. The complete magneto assembly may now be pulled out of crank case. If bushing in breaker plate (SKA-5007) is found worn, entire breaker plate should be replaced. This is easily accomplished by removing contact points, removing four screws (SKA-5017). Entire breaker plate can now be removed. The coil assembly can be removed by removing lead wire screw and the two coil bridge set screws (SKA5054). After removing the condenser (SKA-5047) the coil assembly can. be slid out of case. When replacing coil assembly be sure and have the two countersunk spots on laminations up, so the set screws will seat in them. Be sure and tighten set screws securely and seal with sealing wax. Installing Fan When installing a new fan (SKB-1457) on fan hub (SKB-1455DXA) be sure and have 1/16" timing hole in correct position, that is, 65 degrees to the right (clockwise) from keyway when viewed from pulley end. Disassembly of Saw Sharpener Unit and Inspection of Parts Remove machine screw (G-100-93) on underside of top of main casting (EG-100-1) and lift grinder head off. Remove nut (G-100-56) from right end of shaft (G-100-49). Remove pulley (G-100-62) after loosening Allen set screw in hub. Remove nut (G-100-57) from left end of shaft (G-100-49) Remove flange (EG-100-42) and wheel (EG-100-64), also second flange and spacer (EG-100-50). Remove bearings (G-100-55) by tapping shaft (G-100-49) one way and then the other way. Remove shaft (G-100-49). Remove plate (EG-100-4A) by removing thumb nut (EG-100-11) and bolt (EG-100-33), also remove pin (EG-100-19). Remove swivel head lock (EG-100-10) and indicator plate (EG-100-14). Lift off swivel head (EG-100-2), remove collar (EG-100-13), remove spacer (EG-100-15) and bearing (EG-100-21) by removing bolt (EG-100-32). Remove cotter pin (EG-100-102). Take off knurled nuts (EG-100-9) and (EG-100-8), remove shaft (EG-100-3). Inspect bearing (G-100-55) by placing index finger inside bearing and turning outside with other hand. If bearing does not turn smoothly, replace before reassembling grinder head. Inspect adjustment fingers (EG-100-27). If fingers have lost their tension replace before reassembly. Measure hole in swivel head (EG-100-2). If measurement is over 1.005 inches, replace before reassembly. Inspect shaft (EG-100-3). If measurement is less than .997, replace. Measure spacer (EG-100-15). If measurement is less than .490, replace, inspect frame (EG-100-1) if measurement of shaft hole is greater than 1.005 inches, or slot is wider than .505 inches, replace frame. Other parts of saw sharpener will not require replacement unless breakage occurs. When reassembling saw sharpener unit be sure that indicator arrow (EG-100-14) is pointing to Zero when plate (EG-100-4A) is parallel to grinder shaft (G-100-49). Lubricate shaft (EG-100-3) and spacer (EG-100-15) with cup grease or motor oil before reassembling, being sure all parts are clean. Adjustment and Lubrication Adjustment and lubrication should be according to the instructions given the Operation Section of this booklet. Mounting New Saw Adjustment Fingers The index fingers or saw adjustment fingers mounted on the chain saw track may become injured or unsatisfactory after lengthy use. To mount the new saw adjustment fingers, simply remove the old ones by unscrewing the two screw bolts, affixing them to the chain saw track, being careful not to lose or misplace the two metal spacers. The two new saw adjustment fingers should then be affixed to the chain saw track by screwing in the two screw bolts with the two metal spacers on the inside, one on each side of the track. 27 to 31 |