Description: General Information for Selecting a SEI 205 Replacement Gearcase How to use this chart: Finding the correct replacement for your Mercury Metric series of gearcases can be very difficult. They fit a very large range of engines. The most reliable way of determining which replacement unit you need is to identify which driveshaft your original unit has and what is the gear ratio. For the driveshaft, look up the original equipment part number for your gearcase and find it in the chart above. The gear ratio can be determined by several ways. The most reliable way is to count the teeth on the gears and match the count you find to the chart above. You can also put the gearcase in gear and count how many rotations of the driveshaft are required to turn the propshaft one time. It will either be a little over two turns for the 2.07:1, or two and a third turns for the 2.31 and 2.33 ratios. Finally, some units have the pinion gear tooth count shown on a sticker placed at the back of the lower unit. It will be one of the following: 14 = 2.07:1 13 = 2.31:1 12 = 2.33:1 Description Motor Length D/S OE Part # Spline Count OD of Spline Length of spline D/S Measurement * Gear Ratio Gear Teeth Count SEI Part # Picture Ref # 2 stroke 70-125hp L 45-43031A1 13 .873" 1.440" 22 3/8" 2.07:1 14 - 29 90-205-A20 1 XL 45-43032A4 13 .873" .760" 27 3/8" 2.07:1 14 - 29 90-205-A25 2 L 45-43031A1 13 .873" 1.440" 22 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B20 1 XL 45-43032A4 13 .873" .760" 27 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B25 2 DFI 75-115hp L 45-888933A1 13 .873" 1.635" 23" 2.07:1 14 - 29 90-205-A20D 3 XL 45-888934A1 13 .873" 1.635" 28" 2.07:1 14 - 29 90-205-A25D 3 L 45-888933A1 13 .873" 1.635" 23" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B20D 3 XL 45-888934A1 13 .873" 1.635" 28" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B25D 3 4 stroke 70-115hp early L 45-858765T1 18 .760" 2.390" overall 23 3/8" 2.07:1 14 - 29 90-205-A20F 4 XL 45-878575T1 18 .760" 2.390" overall 28 3/8" 2.07:1 14 - 29 90-205-A25F 4 L 45-858765T1 18 .760" 2.390" overall 23 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B20F 4 XL 45-878575T1 18 .760" 2.390" overall 28 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B25F 4 4 stroke 30-50hp Big Foot 4.25 Bullet L 45-854808A1 13 .873" 1.570" 23 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B20T 5 4 stroke 40-60hp Big Foot 4.25 Bullet L 45-859105A1 17 .748" 1.720" 23 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B20S 6 XL 45-875222A1 17 .748" 1.720" 28 3/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B25S 6 2 stroke 50-60hp Big Foot 4.25 Bullet L 45-826736A1 11 .750" 1.170" 22" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 90-205-B20M 7 LL 45-826737A1 11 .750" 1.170" 24" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 n/a 7 4 stroke 75-115hp late L 45-897679T01 20 .875" 2.200" 25 7/8" 2.07:1 14 - 29 n/a 8 XL 45-897680T01 20 .875" 2.200" 30 7/8" 2.07:1 14 - 29 n/a 8 L 45-897679T01 20 .875" 2.200" 25 7/8" 2.31:1 / 2.33:1 13 - 30 / 12 - 28 n/a 8 XL 45-897680T01 20 .875" 2.200" 30 7/8" 2.31:1/2.33:1 13-30/12-28 n/a 8 * measure from case mating surface to top of driveshaft In the late 90s, Mercury Marine made a change to the metric inline gearcases. The reverse gears and clutches were changed from 3 jaw to 6 jaw engagement. The distance between the forward and reverse gears increased as a result. The existing shift linkage could not account for the increased clutch travel needed. The shift shaft and linkage in the midsection were redesigned to compensate. When replacing a 3 jaw gearcase with a 6 jaw gearcase, the shift shaft and linkage must be updated as well. The Mercury part number for the 6 jaw shift shaft and link kit is 79932A20. This kit includes the shift shaft and link, and all applicable bushings and nuts. Since the powerhead must be removed to replace the shift shaft in the midsection, a new powerhead base gasket must be ordered as well. SEI part number 92-205-07K has all the necessary shift shaft parts as well as a powerhead base gasket. The 205 series SEI units are shipped in the neutral detent position. The hold of the detent is not very strong, which could allow the unit to fall into forward gear or even past the forward gear detent, during shipping or handling. The gearcase must be shifted into the forward or neutral detent before being installed onto the engine. You can tell if the unit has shifted out of the neutral detent by first turning the propshaft. If the propshaft spins freely, the unit is in neutral. If the propshaft locks when turned counter-clockwise and ratchets clockwise, the unit is in forward gear. If the unit is in forward gear and the shift shaft spins freely, the unit has shifted past the forward detent. Turn the shift shaft counter-clockwise until you feel it click into the forward gear detent. If you continue to turn the shift shaft counter-clockwise, you will feel the neutral detent engage. The unit can be installed when in neutral or forward gear. Make the sure the remote control is shifted into the corresponding gear position. Keep in mind that due to the heavy spring loading of the cam follower, that shifting these units is very hard when the driveshaft is not spinning at idling speed (roughly 750 rpm). See the picture below to help understand what is happening in the lower unit. Any reference to Original Equipment Manufacturer (OEM) names, trade names, specifications, or part numbers is for informational purposes only. Sterndrive Engineering Inc. is not affiliated with any of the OEMs referred to in this ad. Copyrights and Trademarks belong to their respective companies. Copyright 2018 Sterndrive Engineering Inc. All Rights Reserved. Powered by SixBit's eCommerce Solution
Price: 25 USD
Location: Oldsmar, Florida
End Time: 2024-08-17T12:51:55.000Z
Shipping Cost: 0 USD
Product Images
Item Specifics
Returns Accepted: Returns Accepted
Item must be returned within: 30 Days
Refund will be given as: Money Back
Return policy details:
Return shipping will be paid by: Buyer
Manufacturer Part Number: 90-405-05K
Brand: Sei Marine Products
Warranty: 1 Year
UPC: Does Not Apply