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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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Posts: 1901
Location: MN | Hey Steve, Thanks for starting this one. I went back and found that old thread regarding 690's and Rev 4 props. As I thought, I was mistaken about the pitch. While 23 was discussed, the guys were convinced that Sled had a 21p on his 175, not a 23, though he didn't weigh in. Hodag got a 21 for his 175, and Lone Star got a 20p for his 150. They all love em.
Mines a '95 150 as you say, and I think the pitch on the Hi 5 is 21. And to hopefully make this easier, it's not speed I'm interested in. We get 51-52 with two guys and gear, and hole shot is good. It's really the bouncing I'm most interested in nipping in the bud, if it's possible. If we just need to regularly bump the throttle and play the trim when she bounces, I'm okay with that. But if that can be eliminated I'm all ears. Problem is it doesn't do it all the time, nor can I reproduce it on a whim, the conditions aren't consistent when it happens. So I can see us borrowing/trying a Rev 4 and not getting it to happen, and not knowing whether it's cured. Until of course I buy it, then watch it bounce out of the blue one day 
So that's where I'm at, if you think I might be good where I'm at that's great. But if I can do better on the bounce that's even better. Thanks again! |
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Posts: 3507
Location: Elk River, Minnesota | Hiya,
A prop with more tip cupping like the rev4 I think has more ability to lift the bow than the high 5. I would bet what is happening is you hit a wave just right and the bow starts the bounce and the only way to settle it is to trim down, killing speed. That is a good indicator the prop is not staying hooked up. If you know your max rpms and top speed, I'd be interested to see what the numbers can tell us.
Steve |
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Posts: 13688
Location: minocqua, wi. | mine is a 21P … we made a mistake and thought we confirmed it in that thread, hope this helps. |
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Posts: 1901
Location: MN | That's what I thought, thanks Sled. Steve, I don't know max rpm's, won't know until this summer. Maybe we'll resurrect at that time. |
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Posts: 176
Location: Tomahawk, WI | Propster, you are right Sled and I are both running 21p Rev 4's. We also both have 175 Optis, and we have great hole shots and no porposing at slow to mid range speeds. I tried a 23p Rev. 4 and could barely get up on plane without feathering the throttle, so I believe you will not turn a 23p. I would recommend a 19-20 pitch for you 150 EFI, maybe you could turn a 21p depending on how strong your motor is. Just my thoughts. |
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Posts: 13688
Location: minocqua, wi. | how bout a day on the water doing prop-tuning with Steve … i'll buy dinner! |
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Location: Contrarian Island | I would think the advice above going w a 19 or 20 Rev 4 would rock... if you want a custom Rev, call DAH Props down by Milwaukee...he makes a killer prop! |
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Posts: 13688
Location: minocqua, wi. | i haven't done any venting at all with mine and don't have the confidence to screw around with it … that's what i'd like to do as a starting point.
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Posts: 574
| I think this thread is making me want a rev 4...
You have a 21p also Brad??
My 690 came with a 23p mirage, not sure I'm completely happy with it..
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Location: Contrarian Island | I would have to look back at the other threads but I think mine is a 21P, custom 4 blade Solas from DAH... it really has great hole shot, and really 'bites' mid range and pins it at about 52 and the load doesn't seem to matter much...
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Posts: 13688
Location: minocqua, wi. | i'm getting similar results with the stock Rev-4, but would like to fine-tune it with exhaust porting and maybe a fine-tune from DAH. it's my understanding that DAH takes a prop that is good and makes it great. is that what you would say Brad?? |
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Location: Contrarian Island | yes, he will make it better than stock... not cheap, but they are sweet
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Posts: 13688
Location: minocqua, wi. | important to note … i run a 175 Pro-XS on the 690C hull and Brad runs a 175 Suzi 4-stroke on the 690VS hull. |
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Posts: 574
| jonnysled - 2/14/2014 9:52 AM
important to note … i run a 175 Pro-XS on the 690C hull and Brad runs a 175 Suzi 4-stroke on the 690VS hull.
Yup, I know.. Mine is a VS with a 175, that why I asked him..
Brad, looking at an older post you said "I ordered a 4 blade Solas 23 pitch that he is going to customize" (dah props)
Might just have to call him and see what he recomends..
Edited by Jason Bomber 2/14/2014 10:23 AM
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Posts: 3507
Location: Elk River, Minnesota | That'd be a fun day Sled!! You got the different plugs? I will be making a trip to Conover sometime in late may early june to pick up a a piece of "fishy" furniture to bring home...
Steve |
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Posts: 176
Location: Tomahawk, WI | Guys, vent plugs are for hole shots only. The bigger the holes in the vents the more exhaust is let out of the barrel the faster the prop spins at hole shot. The more exhaust out the less prop bite, so there is a fine line to this, Sled I believe you have all your vents in without any holes in them? correct. you have a great hole shot so I would leave it alone. For the guys that have vent plugs in with a doggy hole shot may want to start with a 1/8" hole drilled in each and go up from there if required. There is an excellent explanation on the mercury prop website. |
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Posts: 3507
Location: Elk River, Minnesota | Hiya Pantlegger...
I believe we've touched on what the vent plugs are to do (hit it in the 115 thread), but as people are testing, they have to consider what the boat is going to do in rougher seas when the power is needed most. Determining the rpm level when the exhaust will blow by the holes and out the rear of the prop is an extremely important number to know as rougher waters could have someone dealing with a bunch of slip/surging of the boat if they need a specific rpm to get from point A to point B. Knowing that number will help them navigate, and it may mean they decide to downsize their vent holes to best suit their needs Testing High end is not the intent here as the vents don't do anything at that point as blow-by is what should be going on.
Steve
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New thread for Ranger 690 and 150 EFI Mercury (Propster)