Re: 1994 mercury 225 3.0 L Gear Ratio?
Need to do the rotation count method...<br /><br />Turn the drive shaft twenty to thirty times... Mark a line on the drive shaft just above the water pump to give yourself reference... Also mark a line on the prop and the lower unit case...<br /><br />Like I said turn the drive shaft 20-30 times (maybe even more to be more accurate in the end) and as you are doing this keep track of how many rotations you have on the prop...<br /><br />For instance 20 drive shaft rotations results in 12.34 rotations of the prop...<br />20/12.34=1.62<br /><br /><br />The problem might be determining the difference between a 1.62 and 1.64 ratio... So that is why it is better to turn the drive shaft many more revolutions to give you a little bit more difference in the ending prop revolutions for each ratio.<br /><br />For instance...<br /><br />40 drive shaft revolutions/1.62 ratio = 24.69 prop revolutions<br /><br />40 drive shaft revolutions/1.64 ratio = 24.39 prop revolutions<br /><br />You get the idea...<br />If the lower unit is in forward gear you can do the same by turning the prop instead of the driveshft... But it's (drive shaft turns/prop turns) no matter the case..<br />Also, you will have to pull the lower unit off to do this... Have fun!!!!