The following alignment procedure applies to all driveline types on all boats and also explains why some prop shafts are not centered in their stern tubes (hull penetration area). It should be noted engine mis-alignment DOES NOT CAUSE VIBRATION. Vibration is caused by an out of balance portion of the spinning driveline such as the propeller, coupler or shaft if it's bent. A mis-aligned engine causes a constant force to be applied at one angle and will wear out the transmission output shaft bearing, cause the seal to leak and wear away the nitrile rubber in the cutlass bearing.
When a prop shaft is installed at any point in the boat's life, its alignment to its stern tube depends entirely on the position of the strut. If the strut was installed at an angle in relation to the stern tube, the shaft will not be centered through it. Additionally, any misalignment of the prop shaft through the strut from running aground, striking a submerged object or initial improper installation or improper engine alignment will cause damage to the strut bearing, shaft and output gear/bearings on the transmission or v-drive. The damage occurs over time and is directly related to use of the vessel in its adverse condition. Fortunately, checking prop shaft alignment is not very difficult and can be performed both in the water or while the boat's on its trailer and once set, really only needs to be checked again every 300 hours or 5 years. The alignment you will be checking is the space between the propeller shaft coupler and the output coupler from either the transmission or the v-drive.
1) Locate and identify the propeller shaft coupler. On inboards, it's easy to see at the end of the transmission and on a wakeboat, has 4 bolts connecting it to the propeller shaft coupler. On V-drives such as the Walter (either blue or black) the couplers are at the bottom of the v-drive at a 12 degree down angle facing the engine. These will be more difficult to access and check compared to inboards or the newer models. On the newer Raptor engine v-drives, the coupler is located boat forward but at the back of the v-drive.
2) Remove the 4 coupler bolts. It is not usually necessary to remove the bolts because the couplers only need to be slightly separated to check. However, we always suggest a gross alignment check prior to final alignment. Once your initial gross alignment has been verified, you won't need to perform one again unless the engine, transmission or strut have been removed.
Inboard and Walter V-drive instructions
3) Separate the couplers. If the boat is on the trailer, once the coupler bolts have been removed, hop down and pull aft on the propeller about 1/2". You will see polished witness marks on the shaft at the strut and can use those as your gauge. If the boat is in the water and you cannot separate the couplers by hand, replace two coupler bolts 180 degrees apart and hand tighten. Start the engine and briefly pop in and out of reverse one time. This will pull the coupler faces apart but keep the shaft from sliding past the inner alignment flange. Loosen and remove the coupler bolts and use a large flat head screwdriver to create about a 1/2" gap between the coupler faces.
Newer Raptor Engine V-drives
3) Same as above except you will push the propeller forward or put it in forward gear if it's in the water to get the couplers to separate.
4) Observe the gross alignment between the coupler faces. Because the strut "sets" the alignment of the shaft, the couplers should be in visual perfect alignment (shaft angle to coupler faces) at this point. The prop shaft coupler face has a male alignment flange machined into it. This flange locates inside the output shaft coupler. It should be "easy" to join the two coupler faces once the gross alignment is performed and you should not see the prop shaft shift in any direction as the two come together. It's best to have a helper at the prop to push and pull the prop shaft to observed how close the gross alignment is. If there is shifting as the couplers interface, adjust the engine accordingly. If the prop shaft coupler is lower or higher than the engine side coupler, lower or raise the engine respectively. If it is offset to port or starboard, move engine that direction.
5) Adjust the engine using the motor and transmission/V-drive mounts. Locate the engine isolators (commonly called motor mounts) and loosen the large nut on top of the adjustment stud (usually 1" or 1 1/8" nut but different manufacturers have been known to use 15/16". USE THE CORRECT SIZE SOCKET OR WRENCH SO YOU DON'T DESTROY THE NUT!!!!!). We have seen severe cases of rust and corrosion in the saltwater environment, to the adjustment studs and some cases of rust in the freshwater environment. Be sure to evaluate your isolator for viability and replace if necessary. There are port and starboard isolators on the engine side and depending on which driveline setup you have, port and starboard isolators on the inboard transmission, a single adjustment point above the Walter v-drive and a port and starboard isolator set on the newer Raptor engine v-drives. If you want the engine to raise or lower uniformly, adjust each isolator the same number of turns. Adjusting them individually will change the angle of the engine to the prop shaft and only should be done during final alignment or if the gross alignment requires it.
If the engine needs to move port or starboard, identify the isolator location and loosen the horizontal adjusting bolt on the engine side isolators, transmission isolators and/or Raptor engine v-drive isolators. The Walter overhead adjustment point has a slot machined in the bracket which allows the engine and transmission combo to slide port or starboard. Use a large pry bar, 2X4 or anything to make enough leverage to move the engine, against the engine pivoting off the stringer. Once gross alignment is satisfactory, proceed to step 6.
6) Final alignment is achieved by joining the couplers and installing the coupler bolts to hand tight. Get a feeler gauge set and use a single gauge and insert between the coupler faces as you evenly tighten the coupler bolts. Tighten them until you feel resistance against the feeler gauge when you remove it. Use this as your initial check spot. Visualize the coupler faces as a clock (for the general discussion, it does not matter which direction you are looking at the coupler when you clock it but if you describe it to someone or ask a question on it here, PLEASE say "3 o'clock position when looking aft" or "9 o'clock position when looking forward" to describe. The example shows it's the same spot on the coupler but is described two distinctly different ways).
Check if the .020" feeler gauge slides into the coupler approximately every 90 degrees. If it does not fit with the same resistance as your initial check spot, change to either a larger or smaller feeler gauge and check again. The industry standard is alignment within .004" for these size propeller shafts. This means if you start with a .020" feeler gauge and if fits everywhere except one spot which will only take .016", then you're within .004". If .018" fits at the bottom and .022" fits at the top, its within .004". We have seen alignment on these boats up to 1/4" off. NOTE: If your gross alignment requires engine movement side to side, plan on also replacing your strut bearing (also called cutlass bearing).
If your alignment is not within .004" use the up, down and side adjustments described above to move the coupler into position. Once you're within specification, tighten all adjusting bolts and recheck. If everything is still within specification, tighten the coupler bolts and give yourself a pat on the back, you have performed your first engine alignment.
When a prop shaft is installed at any point in the boat's life, its alignment to its stern tube depends entirely on the position of the strut. If the strut was installed at an angle in relation to the stern tube, the shaft will not be centered through it. Additionally, any misalignment of the prop shaft through the strut from running aground, striking a submerged object or initial improper installation or improper engine alignment will cause damage to the strut bearing, shaft and output gear/bearings on the transmission or v-drive. The damage occurs over time and is directly related to use of the vessel in its adverse condition. Fortunately, checking prop shaft alignment is not very difficult and can be performed both in the water or while the boat's on its trailer and once set, really only needs to be checked again every 300 hours or 5 years. The alignment you will be checking is the space between the propeller shaft coupler and the output coupler from either the transmission or the v-drive.
1) Locate and identify the propeller shaft coupler. On inboards, it's easy to see at the end of the transmission and on a wakeboat, has 4 bolts connecting it to the propeller shaft coupler. On V-drives such as the Walter (either blue or black) the couplers are at the bottom of the v-drive at a 12 degree down angle facing the engine. These will be more difficult to access and check compared to inboards or the newer models. On the newer Raptor engine v-drives, the coupler is located boat forward but at the back of the v-drive.
2) Remove the 4 coupler bolts. It is not usually necessary to remove the bolts because the couplers only need to be slightly separated to check. However, we always suggest a gross alignment check prior to final alignment. Once your initial gross alignment has been verified, you won't need to perform one again unless the engine, transmission or strut have been removed.
Inboard and Walter V-drive instructions
3) Separate the couplers. If the boat is on the trailer, once the coupler bolts have been removed, hop down and pull aft on the propeller about 1/2". You will see polished witness marks on the shaft at the strut and can use those as your gauge. If the boat is in the water and you cannot separate the couplers by hand, replace two coupler bolts 180 degrees apart and hand tighten. Start the engine and briefly pop in and out of reverse one time. This will pull the coupler faces apart but keep the shaft from sliding past the inner alignment flange. Loosen and remove the coupler bolts and use a large flat head screwdriver to create about a 1/2" gap between the coupler faces.
Newer Raptor Engine V-drives
3) Same as above except you will push the propeller forward or put it in forward gear if it's in the water to get the couplers to separate.
4) Observe the gross alignment between the coupler faces. Because the strut "sets" the alignment of the shaft, the couplers should be in visual perfect alignment (shaft angle to coupler faces) at this point. The prop shaft coupler face has a male alignment flange machined into it. This flange locates inside the output shaft coupler. It should be "easy" to join the two coupler faces once the gross alignment is performed and you should not see the prop shaft shift in any direction as the two come together. It's best to have a helper at the prop to push and pull the prop shaft to observed how close the gross alignment is. If there is shifting as the couplers interface, adjust the engine accordingly. If the prop shaft coupler is lower or higher than the engine side coupler, lower or raise the engine respectively. If it is offset to port or starboard, move engine that direction.
5) Adjust the engine using the motor and transmission/V-drive mounts. Locate the engine isolators (commonly called motor mounts) and loosen the large nut on top of the adjustment stud (usually 1" or 1 1/8" nut but different manufacturers have been known to use 15/16". USE THE CORRECT SIZE SOCKET OR WRENCH SO YOU DON'T DESTROY THE NUT!!!!!). We have seen severe cases of rust and corrosion in the saltwater environment, to the adjustment studs and some cases of rust in the freshwater environment. Be sure to evaluate your isolator for viability and replace if necessary. There are port and starboard isolators on the engine side and depending on which driveline setup you have, port and starboard isolators on the inboard transmission, a single adjustment point above the Walter v-drive and a port and starboard isolator set on the newer Raptor engine v-drives. If you want the engine to raise or lower uniformly, adjust each isolator the same number of turns. Adjusting them individually will change the angle of the engine to the prop shaft and only should be done during final alignment or if the gross alignment requires it.
If the engine needs to move port or starboard, identify the isolator location and loosen the horizontal adjusting bolt on the engine side isolators, transmission isolators and/or Raptor engine v-drive isolators. The Walter overhead adjustment point has a slot machined in the bracket which allows the engine and transmission combo to slide port or starboard. Use a large pry bar, 2X4 or anything to make enough leverage to move the engine, against the engine pivoting off the stringer. Once gross alignment is satisfactory, proceed to step 6.
6) Final alignment is achieved by joining the couplers and installing the coupler bolts to hand tight. Get a feeler gauge set and use a single gauge and insert between the coupler faces as you evenly tighten the coupler bolts. Tighten them until you feel resistance against the feeler gauge when you remove it. Use this as your initial check spot. Visualize the coupler faces as a clock (for the general discussion, it does not matter which direction you are looking at the coupler when you clock it but if you describe it to someone or ask a question on it here, PLEASE say "3 o'clock position when looking aft" or "9 o'clock position when looking forward" to describe. The example shows it's the same spot on the coupler but is described two distinctly different ways).
Check if the .020" feeler gauge slides into the coupler approximately every 90 degrees. If it does not fit with the same resistance as your initial check spot, change to either a larger or smaller feeler gauge and check again. The industry standard is alignment within .004" for these size propeller shafts. This means if you start with a .020" feeler gauge and if fits everywhere except one spot which will only take .016", then you're within .004". If .018" fits at the bottom and .022" fits at the top, its within .004". We have seen alignment on these boats up to 1/4" off. NOTE: If your gross alignment requires engine movement side to side, plan on also replacing your strut bearing (also called cutlass bearing).
If your alignment is not within .004" use the up, down and side adjustments described above to move the coupler into position. Once you're within specification, tighten all adjusting bolts and recheck. If everything is still within specification, tighten the coupler bolts and give yourself a pat on the back, you have performed your first engine alignment.
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