Lower unit gear ratio 1988 110 Johnson.

[AEROCOOK]

I suspect my "new to me" 1988 Johnson 110 has had the lower unit replaced at some time as the colour is different than the rest of the motor and it looks older based upon it's general condition. I have this motor on a boat that is rated for max 90 hp only, so it's got power to spare and it runs flawlessly at high speed. I did a link and synk on it and have confirmed that the timing is dead on and the motor is healthy. My concern is that in order to get into the desired WOT RPM range (5800/6000) I can only use a 17 pitch 13 and 3/4' prop. I read some other posts about different lower unit gear ratios and some bells started going off in my head. Is it possible that I have a lower unit with a higher gear ratio than my 110 should have on it?
I would like to know what I have, is there any way to tell?
P.S. it's the aluminum bowrider in my avitar.

 

[AEROCOOK]

Re: Lower unit gear ratio 1988 110 Johnson.

Any one?
I just need to know how to figure out my lower unit gear ratio.

 

[Chinewalker]

Re: Lower unit gear ratio 1988 110 Johnson.

Your gear ratio is 13:26. The only other option for a gear ratio was 12:27 on the heavy duty work model which was essentially a V6 lower unit.
Easiest way to check yours is to spin the flywheel and mark how many times the prop rotates. If you get exactly two flywheel rotations per prop rotation, its a 13:26...

 

[AEROCOOK]

Re: Lower unit gear ratio 1988 110 Johnson.

Thanks Chinewalker, thats exactly the info I was looking for.