OMC outdrive parts *Repairing lower unit or replacement
steps 1 to 20
Last updated on 2/24/2023, 2:26:17 AM
- 400-800 OMC boat repair photos
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OMC outdrive parts *Repairing lower unit or replacement
Lower unit is disassembled, and placed into the sandblast area
The outside and inside of the housing is sandblasted, removing all rust and corrosion
For replacement rebuilt lower units, a new propeller shaft (GLM P/N 22414, 1-3/16″) is installed.
For customer units, a dial indicator is used to determine if the propeller shaft is out of round (bent). This would not be visible to the eye when turning so the tool is required. The threshold we use to determine if it needs to be replaced is .004″ out of round. Any more than that, and continued use of the bent unit would damage the oil seals and allow for water to enter the gear case and oil to leak out.
Reverse gear is installed
Pinion gear is installed
For rebuilt units, a new forward gear and pinion are installed.
For customer units, the forward and pinion are inspected for any chips or cracks on the teeth – or excessive pitting that would effect the integrity of the tooth on the gear. If found, a new forward/pinion set is installed.
The forward bearing housing assembly is installed (GLM P/N 27700, replaces 389455). This has the bearing pre-installed into the housing.
A new clutch dog is installed (GLM P/N 22625, replaces 337774).
For customer repair jobs, the teeth (corners) on the clutch are inspected – if there are signs of wear, in which the edges are beginning to or have rounded out, a new clutch is installed. Re-using a worn clutch would continue to cause problems with shifting, possibly loss of forward and reverse or shift cable damage.
The vertical drive shaft is installed.
For customer lower units, the unit is inspected for excessive wear or damage to the threaded area. In many instances, the boat parts can be repaired using a lathe. Shaft must be replaced if it is not repairable.
The swivel housing is installed. It is sandblasted, primed and painted before installation and the face is machined to make sure it seats flush onto the lower unit / gasket.
The upper bearing retainer is installed – cleaned and primed
All gears are shimmed to correct OEM specifications
The intake screen is installed and painted to match outside case color
Zinc chromate primer is used on the inside of the housing
*800 series and Cobra lower unit repair photos.
Click here for steps 21-40 in the repair process