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Posts: 255
| Over the winter I upgraded to a larger nearly new Alumacraft Tournament Pro 185 Tiller. It has the a max hp on it in a 90hp ETEC. I got it out on the water today with hardly any gear in it and got a lousy 32-33mph on GPS with the motor trimmed up. I was really hoping for a little more since the motor is already moved up one hole. I am wondering if anyone is already running this boat with a higher pitch prop. I want to pick up some high end speed. I don't really want to move the motor up any higher since I might suffer too much on hole shot. I beleive it has just a standard aluminum prop. I did not check my RPM at high end and the way I understand it I think I may need to get it out again to check RPM's for pitch sizing purposes. I am not sure when I might get the boat out again in the near future since work is really busy right now. Any help here would be great. Thanks in advance. Tom |
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Posts: 3479
Location: Elk River, Minnesota | Hi Tom,
Having that high end RPM number will be key, along with the gear ratio for the motor and the Max RPM for the recommended range. With those numbers, I can help you some with it.
As far as moving the motor up, you might find your hole shot can potentially increase since the bow may not rise as much. That is what I found when I raised my motor off the transom and it was actually a nicer way to have it.
Being that you are running a fairly sizable boat with a tiller, getting up to 35 to 37 miles per hour might be as good as you will get. I have found that Alumacraft is VERY conservative with their horsepower ratings. My rig, which is just under 17 feet only takes a 90 hp, but could easily handle a 115 to 130hp. What it comes down to is if the boat is submerged, the boat must sit level in the water. Although a larger motor could be used and handled well, it may not keep the boat level if submerged, thus the lower rating.
If you get the chance, though, feel free to post your numbers. Then a starting recommendation can be made.
Steve |
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Posts: 255
| Thanks for the help. The reason I mentioned my hole shot concern was based on my old boat. I had the marina where I repowered my old boat (Alumacraft navigator 165 tiller/ 60hp ETEC) mount it up one hole. I am not a big hole shot guy but, it really did suck pretty bad. I did like the high end power results though. I picked up nearly 7mph. No joke. By the way, I would be happy with 35-37mph. Anyone else? Feel free. Thanks, Tom |
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Posts: 433
Location: Cedarburg, Wisconsin | If you are looking for more top end you need the motor raised as far as it will go and still give you the acceptable water pressure. Without the right height you are wasting your time playing with props. When you on plane and trimmed right, your anticavitation plate must be above the water or at worst just at water level. If it is under water you are wasting power. If I remember correctly quite a few of the E-TECs are running in the 3rd hole. Down side of this is most likely the aluminum prop won't hold on turns at this height. You probably need a stainless prop to get the max height.
Once you have the motor height correct, then you play with props to hit the top end of the specified rpm range or a little above with a very light load. No matter what, the aluminum prop is not what you want unless you are in a minefield of stumps and rocks. You can always run a vented prop for enhanced holeshot, and as mentioned before, with the motor at the right height the holeshot improves.
Go to http://www.etecownersgroup.com/ and read through the forums and you will get tons of good info including all the specs you need for water pressure, rpms, and possibly some recommendations on props.
I ran a very heavily loaded Alumacraft 185 Competitor with a hot 150HP using a 19 pitch SST and only had a 46mph top end, so with a 90 on a similar boat, subtracting 1 mph per every 5HP difference gives you about 34mph. I really believe you should do better than that though. I'd expect to hit around 36 or maybe a little better when you get it set up right. If you are expecting more than that you will be disappointed I'm afraid. |
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Posts: 370
Location: On the River | I have a Alumacraft 175 Mag tiller with a Yamaha 80hp four stroke and a stainless prop it will run 33-34 mph. |
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Posts: 111
Location: somewhere! | Musky53 - 3/31/2010 9:38 PM
Over the winter I upgraded to a larger nearly new Alumacraft Tournament Pro 185 Tiller. It has the a max hp on it in a 90hp ETEC. I got it out on the water today with hardly any gear in it and got a lousy 32-33mph on GPS with the motor trimmed up. I was really hoping for a little more since the motor is already moved up one hole. I am wondering if anyone is already running this boat with a higher pitch prop. I want to pick up some high end speed. I don't really want to move the motor up any higher since I might suffer too much on hole shot. I beleive it has just a standard aluminum prop. I did not check my RPM at high end and the way I understand it I think I may need to get it out again to check RPM's for pitch sizing purposes. I am not sure when I might get the boat out again in the near future since work is really busy right now. Any help here would be great. Thanks in advance. Tom What year is your boat?I run a TP 175 w/ 90hp suzi(4 stroke and approx 410lbs) and top out at 36-38 mph depending on load,14x20 pitch ss prop.What prop are you running??? and how many rpm's are you running full throttle and trimed all thew way up???
Edited by charlesb 4/3/2010 9:07 PM
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Posts: 255
| I have a 2007 Tournament Pro Tiller 185 with 90hp ETEC. I am getting about 31.5 to 32.5 mph at WOT 5300 rpm trimmed up. Evinrude says 5500 is max. I have an aluminum 14.5 x 19 pitch prop. Some guys are saying I am maxxed out. Some say go stainless steel and get 3-4 mph. Some say raise the motor up one hole. Please help.
Edited by Musky53 4/5/2010 12:08 PM
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Posts: 433
Location: Cedarburg, Wisconsin | Evinrude specs the 2007 and 2008 90 HP motors as 5000-5200 rpm for the sweet spot with 5500 max. You should prop the motor to run in the sweet spot for best economy and motor life. How you get there changes the performance.
If you want top end you have to have the motor as high as you can get it and still have water pressure. For the 90 HP you want a minimum of 19psi at 5000rpm and 20psi at 5500rpm. If you don't have a gage you'll never know for sure how high you can run the motor. Once you have the height right then you can work on stainless props to perform at that heigth to get rid of cavitation or blow out on hard turns. You might be giving away up to 3-5mph by running the motor too low.
Or you can just run the motor where it is and prop for 5000-5200 rpm and not worry about the top end. I'd try to run a cupped, vented, three blade 18" pitch stainless if it were my boat, and at least try to raise the motor, aiming for a combo that would let me get to the third hole if possible.
I know it's aggrivating trying different combos of heights and props and it would be so nice if were all spelled out for you but it isn't. It's just part of having a boat. All you can do is set it up the best you can. Not all hulls are the same, not all motors are the same, and not all boats are loaded the same so you can only get a general idea from similar rigs. |
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Posts: 3479
Location: Elk River, Minnesota | Hiya,
I am going to disagree with moving the motor before finding the right prop. Reason being is that if you have a prop that does not do well currently, it will perform worse when you move the motor up. Also, when choosing a prop, find one that puts you at the max RPM while you are loaded with your gear on your own....reason being, when you get a passenger or two, the motor will be operating in the middle of it's RPM range with the extra load. If one were to prop their motor to be in the middle of the RPM range and you get a couple of passengers, the motor might very well be below the recommended RPM range. Result of this will be a hotter running engine, and long term, less engine life.
When searching for the right prop, the best thing one can do is to find a good prop shot that has a demo program...take 3 - 4 different props and head to the water making test runs, noting Max RPM, speed, and handling capabilities. What will happen is one prop will stand out among the others in all categories. THAT is the prop to go to, then work with motor height. A couple of things to consider when re-propping....the higher the motor height, the more rake and/or tip cupping you want to maintain a better bite on the water, and also will help with trimming capabilities. Continue to try different props of different designs until you find one that fits what you are looking for. Once on the right prop, then you can play with pitch if rpm is too high or too low depending on how many RPMs you are over or short. If anything, it would be better to err on the high side because you can always throttle back, whereas if you are over-propped, you lug the engine and make it work harder...less engine life.
As with anything, changing motor height has trade-offs as well. The higher the motor setting, the more slip the prop will have, and thus a small loss of handling capabilities. Optimum motor position is based upon your a cruising speed, where the boat just feels like it floats along, with easy handling and very little trimming in turns. If you go into a moderate turn and the motor starts to ventilate, you either have to trim down a bit (which SHOULD be the case) or move the motor down (not preferred but might be something that does happen). With the right prop, trimming down is all you should need to do.
Steve |
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Posts: 111
Location: somewhere! | we are running the same boat,same dry weight and your motor is 70lb less.i think Steve hit it right with the prop route,try stainless.also when you say trimed all the way up,is the tiller handle stiff or loose?when u punch out its stiff,trim up and it loosens up and when you trim up more to top out it will stiffen back up. |
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Posts: 433
Location: Cedarburg, Wisconsin | When I set my rig up, I played with props, tried 4 different ones. One was a 21" aluminum with no vents, one was a 23" over hub 4 blade stainless, one a 3 blade stainless vented 21" pitch, and a 3 bladed nonvented aluminum 23" pitch. It made hardly any difference at all when I switched them speedwise, less than 2 mph. Rpms changed but the speed didn't. Why? It didn't make any sense! Well, it was from the motor being too low. When I got the height right, then the props made a world of difference, adding about 7 mph finally. So, that's why I say get the height right first. I figure that if you dial the rig in at the wrong height, the prop that works best will probably not work very well at all when you raise the motor to optimum because you will be out of the correct rpm range, again. But I could be wrong, its happened before. |
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Posts: 255
| charlesb,
You mentioned you are running the same boat. What are you getting top end speed? I am really interested.
You guys all bring up good points but again, I am still not sure if it is better to switch out the prop first or move the motor. I may just do both. I may get a different pitch prop, probably stainless steel and also get someone to help me move the motor. I would do it all on the same day. I will first try to switch out props test it. If I don't get what I want, bring the boat back to my warehouse move the motor up drop it back in the water and try both props. I can check for cavitation in turns, hole shot, and top speed at WOT, trimmed, at max RPM 5500. Unless someone has a better idea, Thanks Tom |
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Posts: 3479
Location: Elk River, Minnesota | Hi again,
Question for you on the boat...when you trimmed the motor up at full throttle, did the bow come up easy? If not, that very well could be one main reason why your speed was so slow. Without actually seeing the boat run, it would be hard to determine, but if the boat seems to plow while you are on plane and trimmed up to the point where the motor will ventilate but no speed gained, there might be a tweek to the boat that can be made to get the bow to rise a bit more. It would require the use of a hammer to the trailing edge of the hull, right where it meets the transom behind the rivet line (there will be about 1/4" of aluminum at that point. What can happen is when the hull is riveted to the transom, a slight hook can be made in the hull on the little 1/4" trailing edge. Although minute, it can have a huge affect on the attitude of the hull while on plane and really affect the ability of the motor to lift the bow. To alleviate this, it would be a matter of pounding the trailing edge of the hull upward to close any gap along the transom line. This is not an uncommon thing to do with a riveted hull. By peening up the hull right at the transom, water will flow off of it with less resistance, thus allowing the bow to rise. If the bow is plowing quite a bit, that will keep your RPM's down and you will be well short of the speed capabilities of the boat.
Steve |
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Posts: 255
| Yes, the boat came up nicely. The speed came up and the ride smoothed out like normal. I can watch the side spray move back too. I also looked at the transom where it meets the bottom of the boat and it is a flat and smooth transition. Thanks for the help. |
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Posts: 536
| I heard once that the change from aluminum to steel does'nt make any difference until you reach 45mph? maybe this is untrue? |
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Posts: 3479
Location: Elk River, Minnesota | Hiya,
untrue....anytime you change to a steel prop, you have less blade flexing which adds to the amount of force it takes to turn the prop....which reduces your RPM's on the engine. An aluminum prop will flex more than you might expect, so for example if you are running a stock 19 pitch aluminum prop, it more than likely is acting like an 18 or 17 pitch prop in the water (depending on the blade design and thickness). A stock 19 pitch steel will act like a 19 pitch steel since it does not flex anywhere near as much as a stock aluminum.
So...anytime one changes directly from a stock aluminum to a stock steel, a drop in 2" of pitch is roughly the necessary route. All of that depends on a number of things most notably the style of prop and the combination of pitch and diameter. If those variables change when converting, many different things can happen...which results in doing a bunch of testing and recording of information, then deciding which prop is best for your particular rig. Even two rigs set up identically will have different running characteristics, potentially leading to running two totally different types of props.
Steve
Steve
Edited by VMS 4/12/2010 9:42 AM
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Posts: 255
| OK, I am resurrecting this thread since I was able to move the motor up one hole. I gained 1 maybe 2 mph on top end but it was a little tough to tell as it is really really windy here today. So I am still running an aluminum 14.5x19 prop. I was getting 31.5 to 32 mph at 5200 rpm before I moved it up one hole. I now get 5500 rpm which is max for my motor. I did experience a little cavitation in turns going about 20 mph but nothing horrible. So any further suggestions? Stainless pro maybe? Different pitch? I was by myself with a light load. I usually run with myself and one other guy and medium load. Maybe I should just stay where I am at and be happy with the 33-33.5 mph that I got. Am I working the motor too hard. Thanks in advance for the assistance.
Tom
Edited by Musky53 4/29/2010 4:35 PM
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Posts: 3479
Location: Elk River, Minnesota | Hiya,
If you got to 5500, you are not working the motor too hard at all. With a light load, you are right where you should be.
When you turned and got the ventilation, did you trim down or did you keep it trimmed up? If you kept it trimmed up, I would bet you could trim down just a touch and it would stay hooked up a bit better.
If you go steel, you would see a drop in RPM if you go same pitch, but if you can find a good 18 pitch performance series (yamaha) or equivalent, you could probably raise the motor one more hole and you'd be pretty close to the 5500 yet.
Overall, sounds like the move up is working for you...
Steve |
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Posts: 255
| Steve,
Sounds good. Yes, when I ventilated in the turn, I simply trimmed down and all was good. I rarely need to make tight turns at high speeds. If I do, I will just trim down slightly and all is good. I spoke with a prop shop guy here locally that is very knowledgeable and he said the exact same thing you did. Since I will run with 2 guys most of the time, the RPMs will come down slightly and I will run perfectly where I should. As for the prop, he did not say a steel prop would help all that much. I am going to bring him my aluminum prop and he is going to modify it slightly on the cup to help a little more but that is it. Thanks for all the help. |
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| I have the 2003 185 tournament pro T with a Yamaha V-Max 150 TRP(Dual Props), I run at 4400RPM and 45MPH on GPS. Max rpm is 4500-5000.
Is buying a bigger motor out of the question? If not you could save all the headaches and just slap a 125-150HP on there and easily run 40 plus MPH. |
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| I have a 2002 tp 185 with a 200 honda and I run right at 51 mph, its a heavy boat. |
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Posts: 3479
Location: Elk River, Minnesota | Hi Everyone,
Quick reminder from the beginning of the thread.. The boat is a tiller model... Probably rated to a 125 at most...
Steve |
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Posts: 272
| I've got an '02 TP console with a 115 Yamaha. I believe I've got a 19 or a 20" 4-blade SS and under the best of the best conditions.....I can sometimes brush 40. Normal max at 6-something-thousand RPM trimmed to the max is 38.5mph. With four dudes in the boat and all our gear, I still get 32-35mph depending on conditions, so IMO my boat is set up pretty well. Boat is rated for a 175.
You're running a boat that's a foot bigger, so heavier, more drag, etc. So with a smaller engine and a overall bigger footprint.......
I'm no boat doctor, but I don't think you're too far off what your max would be there. You can putz around with pitch and positioning of your motor, but at what cost.....and for what real gain?
If you need to try something, I'd try props first. Style, blades and design of the prop makes a huge difference.
Above all, I'd go for your ride performance, before I'd go for your top end. A boat that handles well and rides nice is much more important than the 2 minutes faster you'll get somewhere on a 7 mile haul. Honestly, that's what we're talking about here.
Also, if you have a custom cover, keep in mind that raising your motor may mean a bad fit or another trip to the custom cover guy to get it fixed.
-Eric |
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