Posts: 3507
Location: Elk River, Minnesota | Hiya Propster!!
I wanted to address your questions in a separate thread so as not to have the little confusion that was going on in the 115 Etec, I hope you don't mind...
In terms of turning the Rev4...
I am not totally sure on the differences between a 150 efi vs the 175 ProXS, but looking at your original prop (the high five), I think you could potentially try the Rev 4, although I would not be surprised if a 23 pitch might be a couple inches too much in pitch to turn. That prop is quite aggressive for a 4 blade, which makes it a dynamite prop for both handling and speed as it has an awesome ability to lift not only the bow, but the entire boat when the motor reaches the upper end of the power band. It's funny how 25 hp can make the difference, and we cannot forget that the lower end gear ratio plays a part in what prop you can turn as well. I don't know the year of your motor, but what I could find on a little search was the 150 2 stroke EFI carried a gear ratio of 1.87:1. The 175 proXS (unless it has changed in the past years) has the same ratio, so I would suspect the difference in your motors is in fuel injection and compression ratio...that is a good thing as it gives somewhat of a starting point for what to try.
You may very well be able to turn the Rev4 in a 23 pitch... and even better yet, you have options from 15 pitch to 25 pitch, so there is definitely room to work with if the 23 is a touch high. I think overall, you can find a better prop than your current high five you have now as 5 blades on your rig I think is a bit of overkill, and definitely reduces your overall speed. You will never know unless you try, though... I'd be curious as to the pitch of your high 5 to see where you are now and what kind of numbers you are seeing at wide open throttle...
If you find one to try out, plug the holes completely, and start testing. Get both Hole shot numbers, lowest planing numbers, and WOT numbers as well. Then, if you are fortunate enough to have (or order) the different plug configurations, work larger and larger, testing hole shot, mid range, and top end and see what you like best. If you go too large, you will definitely know as midrange performance will become an issue in the 3000 or so rpm range (that range where you really need the "umph" to get the boat up on plane and holding it there). Definitely test the lowest rpm you can go to which keeps the boat on plane. That is the beauty of the vent hole plugs..you can really dial in to what you want your rig to do for the overall conditions you find yourself in.
I know many have been really happy with the rev4 on the 690 series. The gas tank puts a bunch of extra weight up there, which is good for keeping in position while using the bow mount...especially in wind, but it can be a real pain to keep that bow out of the water while running down the lake. That is a lot of weight to keep up in the air...
Steve
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