OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives

New aftermarket SEI outdrive replacement lower stern drives for 4 cylinder, V6 and V8 engines

Last updated on 10/11/2023

  • Sterndrive engineering aftermarket replacement lower gearcase comes with full 3 year fault-free warranty on SEI replacement sterndrives
  • Replacement sterndrives and parts compatible with years 1970 to present models
  • SEI aftermarket Mercruiser, MR, Alpha one and gen ii lower units and replacement upper units. All gear ratios available for all motors, 4 cylinder, V6 and V8 on Mercruiser Alpha one and gen ii lower units
  • No core charge required on new lower/upper gearcases
  • New Johnson/Evinrude replacement outboard lower units
BP-SE106 water pump housing drive shaft

Mercruiser -Alpha one lower unit 1970 to 1990

Replacement sterndrives

Description OEM number

Price
(USD)

Price (Canadian)

SEI Mercruiser lower unit 1623-8951A43

Mercruiser Alpha One lower unit parts

SEI 106 stern drive

P/N SE106
New aftermarket SEI Marine replacement lower unit gear case, replaces Mercruiser lower units up to 1990.

Lower units compatible with 1.94, 1.98, 1.81, 1.65 and 1.50 gear ratios, 4 cylinder, 6 cylinder and V8 motors, up to 300 hp.

SEI lower units have a three year warranty on stern drives.

Note anode is not included with replacement lower unit purchase.

Years 1970 to 1990, Models Mercruiser-1, R MR and Alpha One with serial numbers
2791957 – OD469858

Mercruiser Alpha one replacement lower unit has spline count of 13 on the driveshaft, the pinion tooth count of 13 and drive or reverse gear of 21 teeth.

OEM number 1623-8951A43

$1125.99 US
$1499.89 CDN

Alpha one Gen II lower unit 1991 and up

Mercruiser Alpha 1 Gen 2 lower unit parts

SEI Marine aftermarket outdrive

BP-SE116 prop-shaft bearing carrier

Prop shaft bearing carrier

  • Alpha one Gen ii replacement lower unit.

  • For 1991 and up replacement lower unit with metal water pump impeller housing, serial numbers OD470000-Up.

  • Up to 300 horsepower. Will not replace 2.00 or 2.40 ratio units.
$1199.96 US
$1599.89 CDN

Mercruiser / Alpha One 1970-1990 Upper Gear Cases

SEI Marine aftermarket outdrive

Description / OEM #

Price
(USD)

Price (Canadian)

OEM numbers 1547-9412A20, 1547-9412A21, 1547-9412A22, 1547-9412A23, 1547-9412A19
6 cylinder 165 24-24 gear ratio
6 cylinder 165

P/N SEI 106-1.65

 

SEI Marine aftermarket Mercruiser replacement upper unit.

Compatible with 1970 – 1977 models, 165 horsepower inline 6 cylinder motors, 1.65 / 1.62 gear ratio with a 24-24 tooth count.

Compatible with 165 models serial numbers 2763442 and up.

*Note – before ordering, please measure your output shaft that goes into the engine.

Replacement upper units come with an output shaft that measures 9-9/16 inch.

If your shaft is the ‘short style’ which measures 8-1/8 inches, please contact us for availability.

$1049.96 US includes u-joints and output shaft

$1265.89 CDN does not include u-joints and output shaf

$1399.89 CDN includes u-joints and output shaft

SEI marine 1.98 model

4 cylinder 120 140 chevy

P/N SEI 106-1.98
Mercruiser and Alpha One aftermarket replacement upper unit.

SEI marine upper gearcase compatible with years 1970 to 1990 models, 4 cylinder engines with 1.94 / 1.98 gear ratios with a 20-24 tooth count.

Works with 120 to 140 horsepower models with a 2.5 or 3.0 liter motor, 1971 to 1990, serial numbers 2791957 to 6225576.

*Note – before ordering, please measure your output shaft that goes into the engine.

Replacement upper units come with an output shaft that measures 9-9/16 inch.

If your shaft is the ‘short style’ which measures 8-1/8 inches, please contact us for availability.

$1049.96 US includes u-joints and output shaft

$1265.89 CDN does not include u-joints and output shaf

$1399.89 CDN includes u-joints and output shaft

BP-SEI marine 470 model V6 185 horsepower 17-19 ratio

SEI marine 470 model V6 185 horsepower 17-19 ratio

P/N SEI 106-1.81
Mercruiser R/MR/Alpha One complete upper unit.

For 1976 – 1982 models with 4 cylinder 470 / 485 models and 1986 – 1990 4.3 liter V6. 1.81 / 1.84 gear ratio with a 17-19 tooth count.

Compatible with inline 4 cylinder 3.7 liter motors serial numbers 4208730 to 6225576, and 4.3 liter 185 / 190 horsepower V6 motors serial numbers 6225577 to 0D469858.

*Note – before ordering, please measure your output shaft that goes into the engine.

Replacement upper units come with an output shaft that measures 9-9/16 inch.

If your shaft is the ‘short style’ which measures 8-1/8 inches, please contact us for availability.

$1049.96 US includes u-joints and output shaft

$4.95

$1265.89 CDN does not include u-joints and output shaf

$1399.89 CDN includes u-joints and output shaft

$6.95

SEI marine 1.98 model

1974 - 1990 models

P/N SEI-106-1.50

Mercruiser and Alpha One Gen 1 replacement upper unit.

For 1974 – 1990 models with 205 / 230 / 260 horsepower V8 motors, 1.47 and 1.50 gear ratio with a 20-22 tooth count.

Compatible with 888, 898, 228, 225-S, 233, 250, 260, 5.0 liter 305 and 5.7 liter 350 models serial numbers 2763442 and up.

$1049.96 US includes u-joints and output shaft

$1265.89 CDN does not include u-joints and output shaf

$1399.89 CDN includes u-joints and output shaft

Mercruiser Alpha One Gen 2 1991-Up Upper Gear Cases

Upper Gear Housing Sterndrive OEM numbers 1547-861063A6
1547-861063A12
1547-861063A10
1547-861063A8

BP-SE116 / 4 cylinder 3 litre engine 20-24 ratio

4 cylinder 3 litre engine

P/N SE116-194

Alpha 1 Gen 2 aftermarket replacement upper unit for years 1991 and up.

Models with 4 cylinder motors, 1.94 gear ratio with a 20-24 tooth count.

Compatible with 3.0L and 3.0LX models serial numbers 0D470000 and up.

SEI Mercruiser Alpha 1 Gen 2 aftermarket replacement sterndrive

1991 and up models with 230 / 260

P/N SEI 116-1.47

Mercruiser Alpha 1 Gen ii aftermarket replacement upper unit.

For years 1991 and up models with 230 / 260 horsepower V8 motors, 1.47 gear ratio with a 20-22 tooth count.

Compatible with 5.0 liter 305 and 5.7 liter 350 models serial numbers 0D470000 and up.

Stern drives have 2 year fault free warranty

*Note – does not work with the 305 V8 200 horsepower model.

$1049.96 US includes u-joints and output shaft

$1399.89 CDN includes u-joints and output shaft

$1265.89 CDN does not include u-joints and output shaft

BP-SE116 V6 Chevy motor 17-19 ratio

BP SE116 V6 Chevy motor 17-19 ratio

P/N SEI 116-1.81

Mercruiser Alpha 1 Generation 2 replacement upper unit.

For 1991 – up models with 4.3 liter V6 motors, 1.81 gear ratio with a 17-19 tooth count.

Works with 4.3L and 4.3LX models serial numbers 0D470000 and up.

$1049.96 US includes u-joints and output shaft

$1399.89 CDN includes u-joints and output shaft

$1265.89 CDN does not include u-joints and output shaft

Sterndrive Installation Hardware Parts
SEI now have Mercury Johnson/Evinrude outboard lower units for sale.
Contact order desk and ask about free shipping in Canada
BP-90-106-03K Gen 1 installation kit

Alpha Gen 2 sterndrive installation parts

P/N 90-106-03K SEI 106 Mercruiser / Alpha One Gen 1 outdrive installation parts

Includes:

  1. bell housing locknuts
  2. washers
  3. mounting gasket
  4. intermediate shift shaft
  5. bolt for anode (anode parts not included)
  6. water pump plastic water passage tube
  7. sterndrive locknuts
$99.96
US
$131.89 CDN
BP-90-116-03K Alpha Gen 2 installation kit

Gen 1 installation parts

P/N 90-116-03K SEI 106 Alpha 1 Gen 2 outdrive hardware installation parts

Includes sterndrive parts:
  1. lower unit bolts with locknuts
  2. sterndrive washers
  3. mounting gasket
  4. bell housing locknuts
  5. bolt for anode (anode parts not included)
  6. water pump plastic water passage tube
$80.96
US
$104.89 CDN

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508235 OMC Johnson Compound - 4 OZ

P/N 508235 Gasket sealing compound – 4 FL. OZ (118 ml). This sealant is used on the o-rings and gaskets when re-sealing the outdrive.

 

$29.95

$38.89

Please note warranty provided by SEI

WARRANTY. All products manufactured by SEI are covered by warranty for either a period of one (1) year for upper gear cases purchased without u-joints and output shafts, or two (2) years for lower units and upper gear cases purchased with u-joints and output shafts from the date of actual purchase.

A condition of qualification of these warranties is proof of purchase of the SEI product. Proof of purchase must be supplied by customer prior to warranty application and/or receiving warranty benefits.

These one (1) year and three year warranties against manufacturing defects in workmanship and components are the sole and exclusive warranty provided by SEI and all other warranties and potential damages are limited and excluded. These warranties commence on the shipment date of products to the customer sold by Boatparts.ca to the purchaser.

In the event of a warranty claim, all warranty issues must go directly through SEI, Florida. For more information, see SEI marine sterndrive warranty or limited service or warranty information tel (813) 925-7127 warranty@sterndrive.cc