I hate when this happens

[spareparts]

I/O's are a little more forgiving than OB's with gear ratio changes, they need the correct ratio to perform at their peak, but you can fudge a little by changing pitch and type of prop. First of all, what kind of motor are you running? Second, what prop pitch, diameter, and style are you runnign now. third, what kind of performance were you getting out of your old set up( WOT speed and rpm, cruise speed and rpm). Even if you can't get the 1.50 ratio to work, you might be able to trade it out for someone that has a 1.84 and needs a 1.50. With exception to the 1.5 HD's, the 1.65 gear sets are the strongest.