gear ratio ?

[jims3000]

does anyone know the gear ratio of a 1975 merc 115 inline.

 

[Yepblaze]

Re: gear ratio ?

I think it's supposed to be about 2:1

But being as that motor can use the same housing as on other models, I think I've seen both 1.75 and 2.3:1 affixed and in operation.



A while back..............
Without knowing, I personally recieved a 1.75:1 to use in place of my 2:1 which in turn led to propeller changes. (Call it learning)

 

[jims3000]

Re: gear ratio ?

thanks for the info.

 

[Yepblaze]

Re: gear ratio ?

Without going into hull and load details the prop pitches I've had that associated with the ratios seemed to be roughly about.

1.75 13-15p
2:1 17-19p
2.3 21-23p

 

[Chris1956]

Re: gear ratio ?

Jim, Most of the inline sixes of the seventies were 2::1. The inline 4's were both 2::1 and 2.3::1.