Selectrim System. Chapter Sixteen

Transcription

1 Chapter Sixteen Selectrim System This chapter covers removal and installation of the mechanical and hydraulic SelecTrim systems. Table 1 is at the end of the chapter. OPERATION Trimming describes a change in the stem drive unit's angle in the water relative to the bottom of the boat. Moving the stem drive away from the transom (trimming out) raises the bow in the water; moving it toward the transom (trimming in) lowers the bow. Proper trimming assures maximum performance under given load and sp)eed conditions. Early OMC models are trimmed by adjusting the engine mounts. Later models may be equipped with a power trim system called SelecTrim. On all inline and some older V8 models fitted with SelecTrim, a motorized jackscrew arrangement connected to the front engine mount raises and lo^vers the front of the engine to obtain the desired trim angle. Models without SelecTrim use a similar jackscrew front mount, with the trim angle set manually. All V6 and late-model V8 SelecTrim models use an electro-hydraulic trim system. An electric motor operates an engine-mounted pump and reservoir to provide pressure for raising or lowering the hydraulic actuators under the forward motor mounts. The SelecTrim motor in both systems contains an intemal circuit breaker. This protects the motor from an overload condition if the trim switch is held on after the unit has completed its travel. The SelecTrim system is also protected by the same inline fuse that protects the power tilt system. MECHANICAL SYSTEM If the system is inoperative for any reason, use a hoist and chain connected to the engine

2 SELECTRIM SYSTEM Remove the pillow block lag screws on either side of the jackscrew bracket (Figure 1). 5. Operate the SelecTrim switch until the front mounts clear the engine stringers. 6. If jackscrew pivot shaft is mounted to an engine bracket, remove the snap ring from the shaft end and drive pivot pin out with a hammer and punch. 7. Disconnect the SelecTrim wiring. 8. Remove the jackscrew bracket bolts. See Figure 2 (inhne) or Figure 3 (V6 and V8). Remove the beam and backup plates installed between the engine and engine mount bracket. 9. Installation is the reverse of removal. Tighten fasteners to specifications (Table 1). Coat SelecTrim wire connections with OMC Black Neoprene Dip. Operate system to full HI and full LO positions to calibrate sending unit. lifting brackets to raise and lower the engine as required in this procedure. 1. Raise the front of the engine by moving the SelecTrim switch to LO. 2. Insert a suitable length of 2X4 or other appropriate blocking material under the engine to provide support. 3. Move the SelecTrim switch to HI and lower the engine until it just contacts the support. (Inline Engine Bracket) Refer to Figure 4 for this procedure. 1. Remove the 2 screws holding the rubber mount to the bracket. Separate the bracket from the jackscrew. 2. Push the rubber boot down below the hex surface on the jackscrew. 3. Hold the jackscrew with an open-end wrench and remove the locknut. 4. Remove the stop and rebound washers, spacer, rubber mount and lower spacer from the bracket. 5. Cut the tie strap at the bottom of the rubber boot. Remove the rubber boot. 6. Installation is the reverse of removal. Tighten all fasteners to specifications (Table 1). Bracket (V8 Engine) Refer to Figure 5 for this procedure. 16

3 372 CHAPTER SIXTEEN 1. Remove the tie strap at the bottom of the boot. 2. Rotate the bracket counterclockwdse until the jackscrew is exposed. Clamp the jackscrew in a vise with protective jaws. 3. Remove the roll pin andflangenut (Figure 6) from the jackscrew. 4. Remove the jackscrew from the vise. Rotate the bracket counterclockwise and remove from jackscrew. 5. Remove the boot retainer screws. Remove the retainer and boot. 6. Separate the rubber mount from the bracket with an arbor press. 7. Remove the mount retainer from the jackscrew. ENGINE MOUNT BRACKET (V6 AND V8 MODELS) ENGINE MOUNT BRACKET (INLINE MODELS) 1. Pin 2. Flange nut 3. Rubber mount assembly 4. Bracket assembly 5. Retainer 6. Jackscrew 7. Rubber boot 8. Boot retainer 9. Screw 10. Clamp 1. Backup plate 2. Locknut 3. Stopwasher 4. Rebound washer 5. Spacer 6. Lockwather 7. Bolt 6. Rubber mount assembly 9. Screw 10. Spacer 11. Jackscrew 12. Rubber boot 13. Clamp

4 SELECTRIM SYSTEM 373 SELECTRIM ASSEMBLY 8. Installation is the reverse of removal. Tighten all fasteners securely. 1. Pillow block 2. Jackscrew 3. Boot 4. Trim sender 5. Mount bracket 6. Worm wheel cover 7. Motor SelecTrim Disassembly Refer to Figure 7 for this procedure. 1. Remove the engine bracket as described in this chapter. 2. Invert the SelecTrim assembly bracket and clamp the jackscrew in a vise with protective jaws so that the assembly bracket rests on the vise. 3. Remove the pillow block at each side of the assembly bracket. 4. Unclamp and slide trim motor rubber cover back until you have access to the through bolts, if so equipped. Make alignment marks on the drive end cap and field assembly. Remove the through bolts. NOTE The motor field frame is sealed to the end heads by cemented gaskets. If the field frame separates from the drive end head and armature in Step 5, see Motor Reassembly in this chapter. TRUNNrON HOUSING ASSEMBLY 1. Trunnion housing 2. Shim(s) 3. Thrust washer 4. Thrust bearing 5. Carefully separate motor from trunnion housing. 6. Remove the O-dng seal from the motor cavity on the trunnion housing. 7. Note position of wire clamp and remove the SelecTrim sender from the assembly bracket (Figure 8). 8. Remove the trunnion housing cover screws. Remove the cover. 9. Reach into the trunnion housing and remove the first thrust washer, thrust bearing, second thrust washer and shim(s) in that order. See Figure Remove the worm gear, thrust bearing, thrust washer and shim from the trunnion housing. See Figure Remove the bolt, washers and spacers from the end of the jackscrew. See Figure

5 374 CHAPTER SIXTEEN 12. Unscrew and remove worm wheel from assembly bracket. Remove bracket from jackscrew. 13. Remove jackscrew from vise and clamp bracket in its place. 14. Remove lower bearing from inside of bracket with puller part No Remove a thrust washer, thrust bearing, thrust washer and shim(s) from the braclcet bore. 16. Install puller part No and remove upper bearing from bracket bore. 17. Remove assembly bracket from vise. 18. Clean all parts in solvent and blow dry with compressed air. Replace any components that are corroded, wom or damaged. 1. Trunnion housing 3. Shim(s) 4. Thrust washer Socket WORM GEAR ASSEMBLY 5. Thrust bearing 6. Worm gear SelecTrim Assembly Refer to Figure 7 for this procedure. 1. Install upper bearing in assembly bracket (letter side up) with installer part No and a suitable driver. 2. Sandwich the thrust bearing between the thrust washers and install in the assembly bracket bearing cavity. 3. Install the worm wheel and position shimming gauge part No as shown in Figure 12. Measure the gap between the worm wheel and gauge with a flat feeler gauge to determine the required shim thickness. 4. Remove the worm wheel and thrust bearing sandwich. Install the shiml(s) determined in Step 3, then reinstall the thrast bearing sandwich. 5. Install lower bearing in assembly bracket (letter side up) v^th installer part No and a suitable driver. 6. Clamp jackscrew with its large diameter end facing up in a vise with protective jaws. Coat jackscrew threads with OMC Extreme Pressure Grease and screw worm wheel onto jackscrew. Two flat washers with spring washer between Special toot

6 SELECTRIM SYSTEM 375 Special tool Sandwich the 6 spring washers between the 2 flat washers and install on worm wheel with spacer and boh. See Figure 11. Tighten bolt to specifications (Table 1). 8. Remove jackscrew from vise and install assembly bracket in its place with the large bore facing upward. Install a new O-ring in the bracket groove. 9. Install the worm gear thrust washer and bearing in the trunnion housing bore, then install the worm gear. See Figure Position shimming gauge part No as shown in Figure 13 and measure with a flat feeler gauge. 11. Remove the thrust washer and bearing from the trunnion housing bore. Install shim(s) equal to the measurement in Step 10, then reinstall the thrust washer and bearing. 12. Sandwich the trunnion housing thrust bearing between the thrust washers and install in the housing. See Figure Position shimming gauge part No as shown in Figure 14 and measure with a flat feeler gauge. 14. Remove the thrust bearing sandwich from the trunnion housing bore. Install shim(s) equal to the measurement in Step 13, then coat the thrust bearing sandwich with OMC Extreme Pressure Grease and reinstall in the bore. 15. Apply a light coat of OMC Extreme Pressure Grease to the worm wheel gear teeth. Install the trunnion on the assembly bracket and tighten bolts to specifications (Table 1). 16. Position a new O-ring in the sender unit cover groove. Lubricate the sending unit gear with OMC Extreme Pressure Grease and install to the assembly bracket. 17. Install a new O-dng in the trim motor cavity. Install the trim motor. 18. Check unit operation by connecting tdm leads to a 12-volt battery. If the unit operates properly, reinstall in the boat as described in this chapter. Motor Reassembly Under certain conditions, it is possible that the tilt motor field frame will separate from the drive end cap during removal from the assembly bracket trunnion housing. Use the following procedure to avoid a complete and unnecessary disassembly of the tilt motor. 1. Carefully place field frame assembly on a clean workbench. 2. Remove the drive end cap and armature from the trunnion housing bore. 16

7 376 CHAPTER SIXTEEN 3. If drive end cap gasket is damaged, remove all remnants of old gasket. Clean mating surfaces thoroughly of all residue and install a new gasket coated on both sides 'mxh OMC Gasket Sealing Compound. 4. Carefully separate the commutator end cap from the field frame without pulling the brush leads off. 5. Repeat Step 3 if commutator end cap gasket is damaged. 6. Install armature and drive end cap to the field frame. 7. Position commutator end cap to commutator and push brushes out of the way with a pencil as cap is installed. 8. Install through bolts. Thread suitable nuts on bolt ends to hold assembly together until it is installed to the trunnion bore. Hydraulic Fluid HYDRAULIC SYSTEM The hydraulic system requires a total of 14 ounces of fluid. Pumps used with P^ord engines should be filled with OMC Sea-Lube Premium Blend Gearcase Lubricant. Pumps used with GM engines are filled with OMC Power Trim and Tilt fluid. A certain amount of hydraulic fluid is lost whenever a hydraulic fitting is opened for pump or tilt cylinder service. Use the following procedure to replace the lost fluid. 1. Remove fill plug (Figure 15, typical) and top ofl* the reservoir with the proper fluid. 2. Run trim motor and extend piston rods. Add fluid as rods extend. 3. Install fill plug. 4. Run trim motor to retract and fully extend piston rod. Remove fill plug, top up reserv^oir and install plug. 5. Repeat Step 4 at least 4 times or until reservoir requires no additional fluid with piston rods fully extended. 6. Test pump operation. With a fully charged battery, the engine should reach its fully up position in 9-13 seconds and return to a fully down position in no more than 8 1/2 seconds. Hydraulic Pump 1. Disconnect the negative battery cable. 2. Disconnect the pump electrical connectors. 3. Place a container or rag under the pump hydraulic line connections. See Figure 15 (typical). 4. Mark the hydraulic lines at the pump for correct reinstallation. Disconnect and cap the lines. 5A. V6 models disconnect the negative battery cable from the retainer stud. Remove the pump retainer nut and lockwasher from the stud. Remove the 2 pump screws and lockwashers. Remove the pump. 5B. GM V8 models remove the retaining screws and lockwashers. Remove the pump. 5C. Ford models remove the pump attaching screws. Remove the pump. 6. Installation is the reverse of removal. Tighten all fasteners to specifications (Table 1). Trim Cylinder The following procedures are for trim cylinder removal with the engine in the boat.