Different size engines require different gear ratios in the drive. The manufacturer changes these ratios with different
gear sets. The gear ratio change is in the upper gear housing*. All 1973 - 1985 OMC upper gear housings are
identical** except for the tooth count on the gears and left or right steering worm gear. Below is a chart
showing the tooth count for the different size engines used with OMC sterndrives.
*All lower gear
housing ratios are either 2.0:1 for the four-cylinder engines or 1.83:1 for the six,, and eight-cylinder engines.
**The
original driven gears in 1970 - 1974 upper gear housings are not machined for a centering cone. All
1975 and newer driven gears and all GLM replacement driven gears are machine for a centering cone. A new drive shaft
with shorter splines and a centering cone must be installed when replacing the original (non-centering cone) driven gear.

|
| Rebuilt OMC Stringer 400/800 upper gearcase outdrives |
| 400, 800 and Stringer upper gearcase gears |

|
| OMC 400/800 upper gearcase gear sets |
|
Rebuilt unit includes: New Parts: - Gears (drive / driven)
- Water pump shaft
/ drive shaft
- 4 Bearings
- Oil seals, o-rings and gaskets
- Water pump assembly (impeller housing
and impeller)
- Ball gear, plug, shims and nut
For a complete list of new parts installed,
please see: OMC 800 outdrive page Machined parts: *If drive shaft groves from seal
wear requires machining of more than .010 of an inch or water pump shaft splines male or female are more than 20% worn,
new shafts will be installed into the upper gearcase housing
|
|
OMC Stringer / 800 series rebuilt upper gearcase - low profile $1499.09 *after trade in* OEM # 987242
|
|
Rebuilt high profile upper gear case $1699.09
*after trade in*
|
|
New high
profile Stringer $2499.09 *after trade in*
|