Owner-recognizable problem

Excessive vibration

The outboard vibrates more than expected during operation. Propeller, shaft, fouling, mounting or steering-swivel conditions are possible; this is not a single diagnosis.

Possible causes

Causes are model-specific possibilities, not confirmed diagnoses. Use only the group for your model.

Yamaha F150A

Damaged or unsuitable propeller: Visible propeller damage or a propeller that is unsuitable for the installation can contribute to inadequate power.
Damaged propeller shaft: Visible or suspected propeller-shaft damage is one possible contributor to excessive vibration.
Loose or damaged steering swivel: Loose or damaged steering-swivel components are one possible contributor to excessive vibration and require qualified diagnosis.
Loose outboard mounting: Loose outboard mounting bolts are one possible contributor to excessive vibration and require qualified correction.
Propeller fouling: Seaweed or other material caught around the propeller is one possible contributor to excessive vibration.

What to check next

Check external load and propeller condition — Inspect owner-visible external conditions that can contribute to inadequate power.
Respond to excessive vibration — Stop operation and make a limited external inspection for the source-listed propeller, fouling, mounting and steering conditions.