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14  - 

PRM125

 

9.6.2 Gearcase assembly 

Remove the external Locknut (33)  securing Idler Shaft (2)  into Gearcase. Remove the ten Bolts (36) securing both 
Gearcases (1, 29)  and using a soft mallet lightly tap on the end of the Input Shaft (4)  to separate the two Gearcase (1, 
29) halves from sealant and Dowels (44). Remove the Front Cover (29) . Withdraw the Idler Shaft (2)  the Output Shaft 
assembly  and the Input Shaft (4) . 
 

9.6.3 Input Shaft 

Using a bearing puller remove the two  Bearings (25) ensuring the cups remain with their respective cones. 
Removal of the Bearings (25)  may result in damage them, therefore it is good practice to replace these items if 
removed. (see 9.4.3) 
 

9.6.4 Output Shaft 

Carefully remove “staked” portion of locking device so as to avoid damaging the thread and remove Locknut (30)  from 
Output Shaft (19) . Using a bearing puller remove the Bearing (25) on the output end of the Output Shaft (19). 
 
Remove the following: Thrust Washer (26) , Gear (3) , Needle Bearing (23)  (carefully checking for wear), Thrust 
Washer (22) and  Cone Clutch (21) . Using puller remove the Bearing (25) cone  on the Input end of the Shaft, Thrust 
Washer (26), Output Reverse Gear (20) , Needle Bearing (23) (again carefully checking for wear), and Thrust Washer 
(22) . Save Shims  for rebuild. 
Note: Removal of Taper Roller Bearings may result in damage, therefore it is good practice to replace these items if 
removed. (see 9.4.3) 
 

9.6.5 Idler shaft 

 
Remove Locknut (33) again carefully removing the stacked portion to avoid damaging the thread and supporting Gear 
(24)  on soft material i.e. wood or similar to prevent damage to Gear (24), using a soft mallet tap the Idler Shaft (2)  
through the Gear (24) and remove the Bearing (28) cone . Check condition of the 

‘O’ Ring (49) on the Idler Shaft (2). 

 

9.6.6 Selector 

By hand remove Selector Shoe (9)  and the Spring (8). Remove the Lever (13). Pass the Selector Control Body (7)  
through the Selector Housing (5)  

and remove ‘O’ Ring (12)  and Oil Seal (6)  if replacing them. 

 

9.6.7 Front Cover 

If it is required to replace the Front Cover (29)  then it will be necessary to remove the Oil Seal (34) and Breather (37) . 
If the Bearings (25) are to be re-used then care must be taken not to damage them on removal. The bearing cups can 
be removed with the aid of two levers. It is recommended to fit a new Oil Seal (34). 
Note: When re-fitting Oil Seal (34) set in 1.5mm from face as shown on page 18. 
 

9.6.8 Gearcase 

If it is required to replace the Gearcase (1)  then again if the Bearings (25) are to be re-used care must be taken in their 
removal. Remove Output Seal (31), Dipstick (39),  Drain Plug (46), Filler Plug (46), Level Plug (47) and the two Dowels 
(44) . 
 

9.7 Re-assembly of gearbox 

 
(Note: coat all bearings with clean gearbox oil prior to fitting). 

 
9.7.1 Input Shaft 

Press the two Bearings (25) onto the Input Shaft (4) taking care to position correctly as illustrated.  
 

9.7.2 Output Shaft (see 9.7.5 for shimming procedure) 

All of the following components are fitted over the Output Spline end of the Shaft. 
 
Large bore Thrust Washer (26), Needle Bearing (23), Output Forward Gear (3)  with Cone towards the scroll,  
small bore Thrust Washer (22)  and the Bearing Cone (25) (Press on). 
 
Fit the following components from the opposite end of the Shaft (19) . 
 
The Cone Clutch (21), large bore Thrust Washer (22), Needle Bearing (23), Output Reverse Gear (20) , small bore 
Thrust Washer (26) press on Bearing cone (25) re-shim if components have been changed (see 9.7.5) fit Locknut (30) . 

 

CAUTION: 

Remember to tighten Locknuts to recommended torque. 

(SEE TORQUE CHART 10.2)

 

 

Summary of Contents for PRM125D

Page 1: ...PRM125D WORKSHOP MANUAL...

Page 2: ...and therefore reserves the right to change specifications without prior notification Whilst every effort is made to ensure complete accuracy of the information in this manual no liabilities for inaccu...

Page 3: ...d oils and oil filling 7 5 INSTALLATION 8 5 1 General 8 5 2 Checking the engine Flywheel Housing 8 5 3 Checking the Engine Flywheel 8 5 4 Mounting the Gearbox to the Engine 10 5 5 Alignment to Propell...

Page 4: ...8 Gearcase 14 9 7 Re assembly of gearbox 14 9 7 1 Input Shaft 14 9 7 2 Output Shaft see 9 7 5 for shimming procedure 14 9 7 3 Idler Shaft 15 9 7 4 Selector housing assembly 15 9 7 5 Shimming 15 9 7 6...

Page 5: ...e Ltd direct quoting the serial number CLAIMS UNDER WARRANTY Claims for replacement of parts under warranty must always be submitted with the Gearbox serial number to the distributor who supplied the...

Page 6: ...erial number and should always be quoted when ordering spare parts the lower line is the Gearbox specification in the example given this translates as follows 125 D 2 First 2 digits Gearbox Model 125...

Page 7: ...sification without labouring 1 GENERAL DATA 1 1Specifications Gear ratios ahead 2 04 1 2 50 1 3 06 1 Gear ratio astern 2 44 1 common POWER RATING AHEAD RATIO PLEASURE LIGHT COMMERCIAL BHP kW BHP kW 2...

Page 8: ...facilitate servicing 3 2 Gear train The helical Gear train is manufactured from high grade Steel with all Gears being case hardened for long life All Shafts are supported on Taper Roller Bearings whic...

Page 9: ...elp find solutions to potential torsional problems but it is the ultimate responsibility of the person assembling the drive and driven equipment to ensure that they are torsionally compatible 5 2 Chec...

Page 10: ...9 PRM125 BASIC INSTALLATION DETAILS PRM125D Figure 4 Intallation Details...

Page 11: ...Shaft and stern tube to be maintained Whether a solid of flexible coupling is used it is extremely important that the following points are carefully checked i the Coupling should be a tight press fit...

Page 12: ...use in auxiliary sailboats sailing yachts etc Never put the Lever in the position corresponding to the direction of the Vessel 7 ROUTINE MAINTENANCE 7 1 Initial maintenance after 25 hours running Dra...

Page 13: ...tallation Remove examine and replace if necessary Check the alignment of the Propeller Shaft Coupling if necessary rectify by adjusting the Shims under the Engine mounts or the Engine mounts themselve...

Page 14: ...parts in solvent to remove dirt grease and oil Be careful to remove solvent from items before re fitting 9 4 Inspection 9 4 1 Gearcase Inspect for cracks Check sealing surfaces for any scratches damag...

Page 15: ...Gear 24 and remove the Bearing 28 cone Check condition of the O Ring 49 on the Idler Shaft 2 9 6 6 Selector By hand remove Selector Shoe 9 and the Spring 8 Remove the Lever 13 Pass the Selector Contro...

Page 16: ...haft lengths over Bearings to achieve shim requirement Dimension Y A 6 Fit shims as required to within zero to 0 05mm pre load Place the Shims into the appropriate bore of the Front Cover 29 so that t...

Page 17: ...of the Selector Shoe 9 and the Dog Point Grub Screw 17 at max cone eccentricity CAUTION This condition can only be maintained with the clutch at the top dead centre If this is not achieved the gear s...

Page 18: ...SHER 2 23 0563201 NEEDLE BEARING 2 24 MT8406 IDLER GEAR 1 25 001 0270 BEARING 4 26 0672801 THRUST WASHER 2 27 0320470 INTERNAL SPRING RING 1 28 0540252 BEARING 2 29 MT8621 FRONT CASE 1 30 MT8095 BINX...

Page 19: ...18 PRM125 13 Exploded view and Cross section Figure 5 Exploded view and cross section...

Page 20: ...19 PRM125...

Page 21: ...20 PRM125...

Page 22: ...21 PRM125...

Page 23: ...ODUCTS MT8684 KIT 2 1 MT8684 MT8687 MT8688 FORWARD GEAR REVERSE GEAR CONE CLUTCH PRM120 PRM125 MT8685 KIT 2 5 1 MT8685 MT8687 MT8688 FORWARD GEAR REVERSE GEAR CONE CLUTCH PRM120 PRM125 MT8686 KIT 3 1...

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