Sounds like you have two problems. First is probably fuel filter(s). Bleeding the system (after changing the filters and filling them with fuel) may involve finding the bleed screw on the injection pump and getting the air out of there before you crack open the line at the injector. The location should be in your manual. Generally it's a good idea to shut off the raw water valve while bleeding to prevent sea water from building up in the exhaust manifold and then into the cylinder by way of the exhaust valve. Remember to OPEN the valve when the engine starts. The second problem sounds like the bendix on the starter not engaging if I understand your post correctly. Might be able to just replace the bendix, but knowing marine engine parts you'll most likely have to buy a new starter
