Re: 1.62 Outdrive vs. 2.0
I'm pretty sure if you're turning that much RPM at WOT with those props, that you have 2:0X1 reduction gearing. There's a couple ways to check it, both require some work, one way is take off the top cover of the outdrive, and mark, then count the teeth of both gears, then divide the number of teeth on the top straight gear, into the number of teeth on the bottom flat gear. If the top gear has 1/2 the amount of teeth as the bottom, it is 2:0X1 gearing.
OR, find a way to disable the ignition system, (pull a fuse, or disconnect the main power to it somehow, so it won't run, or damage the ignition, but will crank) then mark the front of the crank pulley with a straight line 1/2 way across the center of the face of the pulley starting at the timing mark with a yellow lumber crayon, put the motor in forward gear, then crank the motor over as a helper watches the prop turn, if it's 2:0X1 reduction, it should be exactly 2 revolutions of the motor, for each 1 revolution of the prop, anything less at the prop, would be less then 2:0X1 ratio. You may want to mark the prop also.
Next, All testing should be done with your trim all the way down, and trim tabs level. If you're turning 4800RPM at WOT, with an 18" pitch 4blade, you're 200rpm over the recommeded rpm! I would suggest a 21 pitch 3 blade prop, because it's easier to spin a 3blade then a 4blade, and this should bring your WOT range down 200RPM, leaving you within the recommended 4200-4600RPM range, and give you a better hole shot, depending on how heavy the boat is loaded. If you are stuck on 4blade props, a 20" pitch 4blade will drop your RPM 200 also, but may not give you the speed, power, and hole shot you want, because of the extra surface area of the 4th blade, especially with 2 of these creating some drag in the water.
As I said previously, you have the power, but you need to get your props up to speed (RPM) under water, as quickly, and efficiently as possible to get you over the hump to plane, a 3blade 21"pitch prop will do this better then a 4blade 20" pitch. I know props are expensive, so if you could borrow some props to try, it would be ideal, or if wherever you buy them , they will allow you one exchange to dial your boat in (some places will do this), that would be the way to go. I'm not going to guarantee these will work for you, but it will in my opinion, check around, and Good Luck
