Gearcase Rebuilding

Gearcase Rebuilding

by Conrad & Judy Kreuter

Q: Dear Boat Talk: I recently had a problem with my lower unit of my outboard which will require a complete rebuild. Being somewhat mechanically inclined, I plan to do the repair myself. What will I need to do the job? VS, Baldwin NY

A: Dear VS: When rebuilding a lower unit, you are dealing with a number of moving components. Gears must be aligned properly so that their contact pattern is correct. This is accomplished by shimming, that is adding or subtracting thin spacers which adjust the location of the gears relative to the others. Some gearcases require an extensive complicated process to accomplish proper gear pattern adjustment.

You will need “special” tools to disassemble and reassemble the gearcase in addition to regular hand tools. These special tools are usually manufacturer specific, that is, they can only be used on the gearcase on which you are working. You must purchase these tools directly from an authorized dealer. A typical set of “special” tools for a gearcase can run up to $1,000. The unfortunate fact is that you probably will never use them again.

Because this is such a technical repair, you should also invest in the “official” manufacturer’s shop manual. These can be purchased from a local dealer and will cost about $45-75.

Once the gearcase has been disassembled, you will need to examine all of the parts to determine which will require replacement. Gearcase parts can also be purchased through the local dealer. A typical set of parts for the gearcase can cost $500-600 and may go higher if the gearcase is severely damaged.

If you have your local mechanic repair the lower unit, his labor will run about $300-400 for this type of repair. The cost of the parts will be the same as above. Doing the job yourself will cost about $800 more than having a professional do it.