Gear Ratio Relationship

[Sea Rider]

Scenario :

2 strokes 50 HP, one with 1.92 gear ratio, the other with 1.85. Both weights same and runs wot at 5850 rpm with same standard factory delivered prop.. if seated on a bare empty combo (300 Kg boat and engine)

What will be the pro and con about going for the one in which the only difference is the gear ratio. Is it all about torque, pushing a heavier boat as opposed to a ligltly loaded one ? Which ratio matches better pushing a heavier loaded commercial/fishing boat ?

Happy Boating

 

[SkiDad]

the lowest gear ratio (1.92) will have more torque - in your case the difference in only 4% so probably not a consideration. I changed my lower unit from 1.73 to 2.0 and the torque is much better for my heavy boat (but I kept the same props i had)

but I'm guessing these are 2 different manufacturers, so i would pick the better brand.

 

[steelespike]

I didn't find any 1.92 50 hp. my info indicates 25 and 30 are 1.92. E/J are 2.42,Tohatsu/Nissan,Yamaha are 1.85, Merc 4 stroke 1.83.
I agree a 1.93 would have a slight power edge. the 1.85 perhaps a slight speed edge if each were on a lighter boat.

 

[Sea Rider]

Both are brand new 2 strokes 50 HP Tohatsus, the one with 1.92 gear ratio corresponds to the Fishing/Commercial model, the one with 1.85 GR corresponds to the Leisure/Recreational Standard model.

Probably will stick with the Leisure model which is intended for 530 mm transoms as opposed to the Commercial which is for 550 mm transoms. Thanks guys.

Happy Boating

 

[Texasmark]

You have your answer right in front of you. Think about the size/weight/hull efficiency of the two different applicartions, usually.