Wrong gear ratio?? What else? long...

[angelo_amalio]

I recently purchased a '94 Caravelle, 17ft bowrider w/ "120hp" 3.0 mercruiser w/an Alpha1. It's very obvious that the lower unit has been changed, just trust me. The motor, having been checked out by local marina, is in great condition. It had a 21 pitch prop and I could only turn 2700-2800 rpm's @wot! So, I buy a 14 1/2 x17 pitch which was recommended by seemingly everyone.. NOW, i get 2800-2900 RPM's @wot!?!? In neutral the boat revs/idles fine. and even under load it runs fine. It just can't pull the rpms... Seems like it's working very hard. Seems to me the whole outdrive, prop and all must've came off a bigger more powerful boat.
Here's my question... Can someone tell me the optimal/factory gear ratio this boat should have? Though I don't know what gears are in it now, not yet.
I do thank you very much for any help!

[admin]

That boat should come with a 1.98 ratio. I believe the tooth count is 20-24. You can pop the top cap off and count the teeth easily enough. You will need to drain some oil out.

Tech Support

[nytdrev.dk]

If you have a 94`boat with a Mercruiser engine and sterndrive, then you have the Gen II version ( from 1991 and up ).

The gearratio - 3.0 litre engine - should be 1.98/1.94 ( 20/24 teeth on the gearset ), and I am sure that your gearratio is wrong since you can´t get the recommand RPM.

Please, see the gearratio in your upperunit drive ( count the teeth on the gearset ).

A propeller with another pitch can´t solve the problem with a wrong gearset in your sterndrive !!!!!

Happy boating.