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How to Replace the Motor and Gearbox Yourself

Mar. 15, 2024

Proper maintenance of your boat engine is important to the longevity of your outboard engine. An important part of proper maintenance is replacing parts with quality OEM boat parts. While the savings of buying aftermarket parts online may be tempting, it will usually cost more in the long run when your boat breaks down and needs further repairs.  


Avoid some mistakes

When you need to replace your outboard lower unit, refer to these mistakes to avoid.

Avoid replacing your external drive or low unit with an overseas aftermarket unit.

Avoid buying refurbished units with aftermarket parts. You get what you pay for and you need quality parts in your drive.

Avoid buying used equipment that has not been completely rebuilt. Without new internal parts, it will cause you problems in the near future.

Avoid buying any unit that is already in the brine.

Look for companies that have perfect after-sales service to save you money


How to Replace the Motor and Gearbox Yourself

                                                                  CG C SERIES COLORFUL OBM ----BLACK 20HP OUTBOARD MOTOR 



Engine unit replacement


The main part of an outboard lower engine unit is really nothing more than a gearbox. The gearbox is also known as the "business end" of the boat's lower unit. When most boaters talk about replacing the lower unit, they are talking about disconnecting the speedometer cable, removing the gearbox, and replacing the old, worn gearbox with a new or rebuilt/remanufactured gearbox. It is always important to purchase the correct lower unit parts needed for repair and replacement.


The first thing to do is remove the key from the ignition switch and pull out the emergency lanyard, which is the cord that clips to the operator's life jacket from the emergency stop switch. Next move the control handle of the engine to the neutral position. Now use a socket wrench to remove the strut and gear box.

Locate the fitting coming out of the top of the front side of the gear box and pull the ends apart. Remove the bolt under the trim tab mounting location and remove the two bolts on either side to remove the gear box. Now wipe the drive shaft and shift shaft splines with a rag greased with lithium grease. Visually inspect the control handle to make sure it is in neutral.


When the driveshaft reaches the crankshaft, gently push the driveshaft up into the middle of the motor. When the crankshaft and driveshaft are realigned, lower the driveshaft enough to insert the speedometer into the hole where the shift shaft aligns, push the gearbox all the way up and tighten one bolt to maintain alignment. Replace the prop.


Finally, set the motor control handle to the forward position and try to rotate the strut. The strut should not rotate. Return the control handle to the neutral position; the strut should rotate freely in both directions. Set the control handle to reverse. The prop should not move.


How to Replace the Motor and Gearbox Yourself


With initial fund of 35 million, a factory covering an area of 9975 square meters and advanced production line in China, Calon Gloria can realize an annual production capacity of 30000 pieces. Please contact us for a quote, and we'll respond asap. If you have any other questions about boat and motors, welcome to consult, too.