Transmission gear ratio

[Ken Cross]

I have a 1989 Hunter 30 and I'm wondering how I can find out my gear ratio. I understand more than one transmission could be installed and I can't seem to find any identifying marks on it.

My reasoning is if I were to replace the prop, the gear ratio is one variable I would need to know.
I do know that my current prop is a 15 x 12 RH 2 blade. It can now make 3,400 rpm while it's clean.
Ken

 

[whatfiero]

It's on a plate top of transmission right above yellow dipstick mine 2.62-1

 

[Ken13559]

Put a mark on the prop shaft coupling and count the turn as you slow hand crank the engine in gear by 1 turn. That should give you a good idea whether the forward gear ratio is 2.62, 2.02 or 3.xx

KenY

 

[Benny17441]

Do you have a Yanmar? What model?

 

[Ken Cross]

Put a mark on the prop shaft coupling and count the turn as you slow hand crank the engine in gear by 1 turn. That should give you a good idea whether the forward gear ratio is 2.62, 2.02 or 3.xx

KenY

Yes, I have a Yanmar 2GM20F I'll look again when I get back onboard.
Thanks
Ken

 

[Ken Cross]

Thanks guys. There it is! It's a Kanzaki KM2p at 2.62

Ken