I'm going over the whole engine, the PO had tried to stop a coolant leak with additives that really just clogged everything. The leak had caused a lot of rust on the starter
so I wanted to have it rebuilt to avoid future trouble. My manual says I have a 107, but a buddy says it may be a 109 industrial unit. In any event, they are all pretty much the same. Although the side the starter
is on can be different. Mine is on the port side under the manifold, which I'd removed for access. The stud length caused the removal problem because it limited clearance, I think I'll try to screw it in a 1/4" or so more, or maybe replace it with a slightly shorter one.
The Perkins engines are pretty much bullet proof, it's the bolt on parts that are more likely to fail. Apart from the rust, the only thing I found "wrong" on the starter
was the inner solenoid was loose. The bendix was like new and the flywheel looks fine. I've been working on the boat for a couple of years, a 32' Challenger, and am finally close to finishing, least as close as one gets with a boat.