![](https://ymlowerunit.com/wp-content/uploads/2024/02/92-304-05-150x150.jpg)
PROPELLER SHAFT ASSY
February 12, 2024![](https://ymlowerunit.com/wp-content/uploads/2024/02/92-305-05-1-150x150.jpg)
PROPELLER SHAFT
February 12, 2024
Description
- Function: The LOWER DRIVESHAFT transmits rotational power from the engine’s powered to the lower unit gearbox. It converts the engine’s vertical drive motion into horizontal rotation, which drives the propeller and generates thrust to propel the watercraft forward.
- Construction: Typically crafted from high-strength stainless steel or marine-grade alloys, the LOWER DRIVESHAFT is engineered to endure high torque loads and resist corrosion from exposure to water and marine elements. It features precision-machined surfaces and splines for secure coupling with other drive train components.
- Design: The LOWER DRIVESHAFT is a long, cylindrical shaft with splines or keyways at both ends. One end connects to the engine’s powerhead via the crankshaft, while the other end mates with the input shaft of the lower unit gearbox. Some designs may incorporate universal joints or flexible couplings to accommodate varying drive angles.
- Splines and Couplings: The splined ends of the LOWER DRIVESHAFT engage with corresponding splines on components such as the crankshaft and gearbox input shaft. This secure coupling ensures efficient power transfer while allowing for axial movement to accommodate engine tilt and trim adjustments.
- Sealing and Lubrication: Seals are employed at both ends of the LOWER DRIVESHAFT to prevent water intrusion and retain lubricating oil within the gearbox. Proper sealing is crucial to maintain lubrication levels and protect internal components from corrosion and wear.
- Compatibility: The LOWER DRIVESHAFT must be compatible with the specific make, model, and horsepower rating of the outboard motor or sterndrive system. It should match the spline count, diameter, and length requirements of the engine’s crankshaft and the gearbox input shaft.
- Installation and Maintenance: Installing or replacing the LOWER DRIVESHAFT requires precise alignment and torque specifications to ensure optimal performance and longevity. Regular inspection for wear, damage, and proper lubrication is essential for reliable operation and to prevent costly repairs.
- Critical Component: As a critical link in the propulsion system, the LOWER DRIVESHAFT plays a pivotal role in converting engine power into forward motion. Any damage or malfunction to this component can lead to loss of propulsion and potential safety hazards while on the water.