Basics first. 1993 rinker captiva 186. Original 4.3 now has 5.0/lx. Sticker is missing from out drive that gives ratio. I only have the serial number 0F053311 which tells me it is an alpha 1 gen 2.
I have ran 2 props both stainless both 21" pitch.
Stiletto 21" 5200 rpmWOT 55mph per gps
Quicksilver Mirage 21" 5000 rpm 50mph (still pushes to 5200 rpm WOT)
Both tests 1/2 tank. Mirage prop done with 100 extra pounds in boat.
The first run with the stiletto prop figuring 1.61 ratio puts me at 14.87% prop slip. 1.81 would be 3.73% slip which is impossible. This particular prop is a bit worn as well.
The Mirage prop figures give me 8.98% slip with 1.81 ratio. This prop is really decent shape. It figures 19.04% slip at 1.61 ratio which is highly unlikely.
So I have two test runs with two props both suggesting two separate gear ratios. I really need to get this figured out so I can get the right prop on there to lower my rpm. I'm also a speed enthusiast and see no reason this can't be a 60mph boat being since I am underpropped as is. Mercury website suggest I use a 23" prop it will put me at 4800rpm WOT.
I am assuming it is the factory drive for the 4.3 and would like have the lower ratio of 1.81, please help! Thank you in advance.
Also, I have a concern of my tach being off, could this be likely? The boat was modified by an engine builder/ mechanic at a marine dealership I trust it is all put together as it should be.
I have ran 2 props both stainless both 21" pitch.
Stiletto 21" 5200 rpmWOT 55mph per gps
Quicksilver Mirage 21" 5000 rpm 50mph (still pushes to 5200 rpm WOT)
Both tests 1/2 tank. Mirage prop done with 100 extra pounds in boat.
The first run with the stiletto prop figuring 1.61 ratio puts me at 14.87% prop slip. 1.81 would be 3.73% slip which is impossible. This particular prop is a bit worn as well.
The Mirage prop figures give me 8.98% slip with 1.81 ratio. This prop is really decent shape. It figures 19.04% slip at 1.61 ratio which is highly unlikely.
So I have two test runs with two props both suggesting two separate gear ratios. I really need to get this figured out so I can get the right prop on there to lower my rpm. I'm also a speed enthusiast and see no reason this can't be a 60mph boat being since I am underpropped as is. Mercury website suggest I use a 23" prop it will put me at 4800rpm WOT.
I am assuming it is the factory drive for the 4.3 and would like have the lower ratio of 1.81, please help! Thank you in advance.
Also, I have a concern of my tach being off, could this be likely? The boat was modified by an engine builder/ mechanic at a marine dealership I trust it is all put together as it should be.
Last edited:
