Re: starter bendix spins does'nt engage 120hp force
Most of the time when the bendix spins and doesn't engage, it's a low battery. It takes a full 12.2+ volts to really kick the starter. Once the battery is charged, put it back in the boat and see if it engages. If it does, battery (or charging) issue. If it still doesn't engage, then look toward your starter and connections.
When dealing with the battery charge, you need to make sure it not only holds a full charge, but also has the power under load. Load test the battery before any further trouble shooting. They will do it for free at all auto parts stores and even Wal-Mart will also.