Sep 22, 2026
Yamaha 15HP Lower Unit Parts | Gear Set, Drive Shaft & Propeller Shaft
Yamaha 15HP lower unit parts including forward gear, reverse gear, pinion gear, drive shaft, propeller shaft, bearings, oil seals and complete gear case assembly.
Yamaha 15HP Lower Unit & Gear Case Parts
The lower unit transfers engine power from the crankshaft to the propeller.
Because it operates under high load and is continuously exposed to water, the lower unit is one of the most important areas of an outboard motor to maintain correctly.
We supply Yamaha 15HP lower unit parts for gear case repair, transmission rebuilding and complete lower unit replacement.
Main Lower Unit Parts
Our product range can include:
- Complete Lower Unit Assembly
- Gear Case Housing
- Drive Shaft
- Propeller Shaft
- Forward Gear
- Reverse Gear
- Pinion Gear
- Gear Set
- Clutch Dog
- Shift Rod
- Shift Cam
- Bearing
- Needle Bearing
- Oil Seal
- O-Ring
- Bearing Carrier
- Water Pump Components
- Propeller Hardware
Drive Shaft
The drive shaft transfers engine rotation from the powerhead down to the lower unit.
A damaged or worn drive shaft can cause:
- Abnormal vibration
- Transmission noise
- Poor power transfer
- Lower unit failure
The shaft should be checked for straightness, spline wear and corrosion.
Forward Gear, Reverse Gear & Pinion Gear
These gears control power transmission to the propeller.
A typical Yamaha 15HP gear set contains:
- Forward Gear
- Reverse Gear
- Pinion Gear
Common symptoms of worn gears include:
- Grinding noise
- Difficulty shifting
- Engine jumps out of gear
- Metal particles in gear oil
- Abnormal lower unit noise
For heavily worn gear systems, replacing a matched gear set may provide more reliable operation.
Propeller Shaft
The propeller shaft connects the gear set to the propeller.
A bent shaft can cause:
- Propeller vibration
- Oil seal leakage
- Bearing wear
- Lower unit damage
If the propeller has experienced a strong underwater impact, the propeller shaft should be inspected.
Oil Seals & Bearings
Lower unit seals prevent water from entering the gear case and stop gear oil from leaking.
Important sealing positions include:
- Drive shaft oil seal
- Propeller shaft oil seal
- Bearing carrier seal
If gear oil becomes milky or cloudy, water intrusion may be present.
The oil seals should be inspected immediately.
Complete Lower Unit Assembly
A complete lower unit may be a practical replacement when the original gear case has:
- Severe impact damage
- Housing cracks
- Major gear damage
- Extensive corrosion
- Multiple internal failures
Lower Unit Maintenance Tips
Regularly inspect:
- Gear oil condition
- Oil seals
- Propeller shaft
- Drive shaft
- Bearings
- Gear engagement
- Water pump components
Correct maintenance can significantly extend lower unit service life.
Yamaha 15HP Lower Unit Parts Wholesale
Available for repair shops, dealers, marine distributors and importers.
Send us:
Yamaha 15HP Model + Part Number + Required Quantity
for part identification and quotation.
