Hi torque starter only 3 seasons on it. 489 with 30 hrs. 2 AGM batteries with switch (2 seasons on batteries), hooked up to trickle charger 24/7 while in the slip. Today for the first time, as I hit the key it makes a clicking sound, however it turns the engine over enough to start it.

In the past with other cars or boats, whenever I got clicking (low battery) , that's all i got, just clicking, but no cranking...now I'm getting a combination of both. Any ideas. This an an 89 mercruiser bravo with a 489 with 30 hrs.

Check the battery cables for corrosion/good connections. You may be getting just barely enough current to turn it over.

X2 also check the ground cable going to the back of the engine, and make sure the + cables are all tight including the post on the starter

checked all the cables, cleaned connections. Still doing it. It doesn't do it when the batt switch is switched to all, but it does it when one battery is selected.

Generally this is a power problem, be it ground or power. From what you describe I would bet its a corroded ground wire, but could be other items. Especially salt water/air moisture can get into a starter and seize the brushes inside the brush-holder not allowing them to move and make contact with the commentator on the armature.They could be seized many starts ahead of noticing the initial problem due to the fact that the get locked in place while they are tight to the armature. After several uses the brushes wear just enough to not make the proper contact any longer and you will experience a no start or intermittent problem. The solenoids can also go bad causing a click, but usually not rapid clicking. You can test to make sure the starter still works by applying power directly from a source such as a battery by jumper cables. This will engage the starter, but be careful. Oh, and if your wondering if you should beat on it I would say most likely its a permanent magnet starter that has magnets glued to the inside of the case and if you strike it you will most likely destroy these on the first go around so DO NOT HIT. If it has screws that go through the body of the casing then you could tap on the side of the starter to see if jarring it will free up the issue. With screws in the side of the body the fields are held in with pole shoes, not glued magnets, and you will not damage the actual starter. I hope this helps..... Ive grown up in the Automotive business and we used to run a rebuilding shop. Good luck!

clicking whyle cranking?? i have seen this on the race style starters,,usually a chip tooth on the bendex..

I think hes talking about rapid clicking without turn-over...

You are getting closer, eliminate the switch, try each battery separately. You've eliminated pretty much after the switch...should be easy now. Is the switch connected properly?

you probably cooked the batteries charging them constantly.

its not the batteries, I took them both in for testing and they tested fine. The charger is a "smart" charger that only charges when the batteries are down. I sanded and cleaned then ground connections and actually the moved the ground to the back of the cyl head vs the bellhousing where it was before, and the cranking is much stronger, however still getting the clanking metal sound while it cranks...its sounds like someone banging a wrench on the starter rapidly as it cranks. Its a starter with 2 seasons on it from DB Electrical. It was only $79 and I am starting to think I got what I paid for, and cheaply made starter!!!