In most cases this is a direct result of overlooked maintenance programs and or absentmindedness.
Case in point - At first sight one might guess that the Mercury V8 engine was seized, with a fully charged battery all the starter could offer was a loud groan and no rotation.
On closer inspection it was discovered that the engine refused to turn over because the alternator and most of the belt pulley bearings had seized.
A quick slash of the multi-groove alternator belt, and wallah! the engine sprang into life.
Step 1. Replace the alternator.
Deep seated corrosion.
New alternator and idler pulleys.
Step 2. Fit new multi groove belt and belt pulleys.
Bilge pumped out and ready to rock n' roll.
Clean-up all the corrosion and replace derelict parts.
Replace a number of water hoses and clean out debris that has found it's way into the water pump housing.
Fair sailing Captain!
Christie Pacific Marine.