OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives

Johnson/Evinrude & Mercury outboard motors lower units
Mercruiser/Alpha 1/Generation 2 outdrive drawings
OMC Cobra stern drive, Electric shift & 400/800 OMC parts

Last updated on 11/11/2023

Search by part number or description here

   1986 to 1993 OMC Cobra outdrive parts

Lower unit exploded view

 Transom shifter parts

OMC gear sets

Cobra water pump kits

 OMC Cobra bellows kit

400/800 outdrive parts 1978 to 1985

Lower unit parts drawing Select 3.375 or 4.250 inch hub size

Intermediate housing

Stringer electric shift upper lower unit years 1972 to 1977

Gearcase seal kit

Gear head assembly

Shift cable wire

Stringer electric shift

1970 to 1983 Mercruiser outdrive parts

Mercruiser Alpha One

Mercruiser lower gearcase

Mercruiser bell housing

1984 to 1990 Mercruiser Alpha One outdrive

Upper gearcase

Mercruiser Alpha 1 lower unit
parts drawing

OMC outdrive repair, OMC parts, SEI sterndrives, Mercruiser outdrives, Johnson water pumps

SEI-106 Mercruiser Alpha 1 upper gear case

SEI 106 Aftermarket lower unit

1991 and up Mercruiser Alpha 1 Gen 2 outdrive components

Alpha One Gen 2 Upper Unit

Alpha 1 Gen 2 Lower Unit

Mercruiser and Alpha
tech drawings
Upper lower gearcase drawings
1967 to 1983 Alpha 1
1984 to 1990 
Generation 2 1991 and up exploded view drawings

SEI 116 Mercruiser Alpha One Gen 2

V6-V8 Mercruiser exhaust manifold-riser applications *Engine bellows applications 4.3 to 5.7 liter

Riser screws & gasket

Mercruiser exhaust manifold

Mariner / Mercury outboard parts

Mercury outboard tools and parts

Seal kit 35-70 hp.

gear set

Evinrude/Johnson water pump and seal kits

87600 Johnson outboard seal kit

Water pump kits

Powerhead gasket set

Gear sets

Outboard tools

12050 Johnson outboard water pump kit

401112451 Oil pump

What,s New
  • SEI Marine products including aftermarket Mercruiser Alpha One and generation 2 outdrive boats
  • Have a new aftermarket OMC Cobra and OMC 400/800 parts for lower unit gear case
  • Upper – lower units SEI gear-case are OEM outdrive replacement for both Mercury and Johnson / Evinrude
  • We carry all inboard-outboard upper gear case gear ratios for Outboard Marine Corporation 4 cylinder, 6 cylinder and V8 engines up to 300 horse power
  • Upper unit can come with and without the 9 9/16” long yoke on the upper drive shaft.
  • Our complete drive shipped in two pieces and will require an installation kit the includes nut kit, mounting gasket and mounting bolts. Other accessories like anodes and shift cables need to be ordered separate

New Mercruiser Repair Tools

  • Mercruiser repair tools including P/N Keen 75057 3″ Scotch-Brite polishing wheel. Used for the inside upper gearcase bearing area on Alpha 1 and Alpha One Gen 2 outdrives. Scotch-Brite area must be cleaned with lacquer thinner to remove small particles and allows bearing, yoke and gear assembly to side in to upper gearcase. Note polishing and cleaning wheel will require the use of any 1/4 ” or larger electric drill and should be use at highest rpm setting.
  • Piston ring installer is used to line up a bearing during bearing and yoke installation
  • 3/16 inch retainer wrench that’s painted black. Spanner nut wrench and bearing retainer wrench installs and removes drive shaft bearing retainer on MC-1 / R / MR / Alpha 1 / Alpha 1 Gen 2, Blackhawk, and Bravo OEM: 91-17256
  • Universal puller plate. Pulls gears and bearings OEM: 91-37241
  • Seloc manuals for Alpha one or generation 2
  • Complete rebuild package for 1.50 / 1.47 gear ratio for V8 models 20 / 22 tooth count for years 1974 to 1990 serial numbers (3856268-0D469858)
    Parts included:
    11210 Gear set
    87500 Seal kit
    39590 Mounting gasket
    21560 Bearing, 21520 Bearing and 21510 Bearing
    23260 Shims, 23270 Shims and 23280 Shim set

Sterndrive Repair

  • 400/800 Series upper gearcase OMC repair including sandblasting, ball gear bearing shims, driven gear bearing shims and plastic ball gear retainer shim kit
  • Boat repair price listed on rebuild and re-manufactured gear cases with quick shop turn around times. Any questions please contact order desk for details
  • Gear cases are painted with two coats zinc chromate primer and two coat of epoxy white paint or color match metallic paint.
  • All gear ratios available for 400/800 Series upper gearcase OMC repair upper units for years 1970 to 1985
  • Pricing includes left or right handed worm gear with half moon steering gear installed with the top cap
  • Includes all labor, welding bearings, seals, replacement ball gear, water pump assembly kit parts
  • Note – additional parts may be required if necessary. Please see parts breakdown page for additional part pricing
  • OMC Cobra sterndrive repairs and OMC parts
  • We have common new and used boat parts in stock for electric shift lower units years 1968 to 1977

Electric Shift Outdrive parts

  • We specialize in 400-800 Electric shift repairs and parts, Cobra and Mercruiser upper gear case and lower unit repairs / rebuilds and carry a full line of used parts
  • We also carry a full line of GLM Marine aftermarket Mercruiser / Alpha 1 outdrive units. Johnson, Evinrude, Yamaha and Mercury outboard parts

Johnson outboard parts

  • We now carry Johnson Evinrude outboard gears, seal kits, Sierra water pumps, propeller shafts and tools. GLM now carrier stainless steel and aluminum fuel filters with 100 micron screen
  • OMC exploded view drawings for all outdrive models including Outboard Marine Corporation OEM numbers makes finding your stern drive part easy
  • Mercruiser parts catalog and GLM Marine Johnson / Evinrude parts catalog and 400 800 Stinger series OMC parts


  • Shipping Cost to US / Canada / International
  • 2 day shipping to anywhere in the United States