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Posts: 29
| I have a Triton 177 with a heavy Suzuki DF150 on it. I have had balancing issues with it from day one. Hits rev limiter, bounces alot, leans to the left and digs very hard when in heavy waves. To get to the point I am looking into trim tabs to solve this issue of the leaning and a jack plate for the rev limiter problem.. I haved switched props. Anyone one had good sucess with trim tabs? |
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Posts: 32901
Location: Rhinelander, Wisconsin | Prop. Classic symptoms. Earl doesn't own Triton, and hasn't for a long time. |
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Posts: 299
Location: Not where I want to be! | Motor may be too deep. Had similar issues with a Ranger and suzuki. Run only half to two thirds of the prop in the water.
My experiance was with the motor too deep, it would act like an anchor and keep dragging the bow down after it raises up, and it just keeps cycling. Mine also had a list to port.
As to rev limiter that is prop as Steve said.
Edited by wavridr 12/10/2012 7:35 AM
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Posts: 32901
Location: Rhinelander, Wisconsin | It's rigging for sure. Most of the time, the listing and porpoise problems combined indicates a mismatched prop; you can get a kit from Mercury and run Merc props on that motor, might be worth a try. As mentioned above, one hole up wouldn't hurt if the engine is flat to the transom. |
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Posts: 175
Location: Tonka, MN | I was indicating multiple problems with the boat. I have gone up from a 21P to a 25P ( I need to go to a 29p to resolve). My opinion is the motor isn't in deep enough. hence the jack plate and hence trim tabs for the lean issue. |
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Posts: 32901
Location: Rhinelander, Wisconsin | Same boat? Why two logins here?
The prop can and frequently does cause a lean issue because of several reasons, including not near enough lift and excessive prop torque, which won't allow the boat to run properly, and it's too small a wheel which can contribute to porpoising as well. it's doubtful the engine needs to be any lower than flat on the transom. Very doubtful.
I am betting you don't need trim tabs. You need to get the boat propped correctly and engine height figured out. Folks don't realize how critical it is to the performance of the boat to have it propped and rigged right, especially running a V6 4 stroke.
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Posts: 175
Location: Tonka, MN | Its his brothers account! Must of been a mistake. |
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Posts: 3488
Location: Elk River, Minnesota | Hiya,
There are a few things that come to mind here with the set-up that I think should be explained a bit further in detail, which may help clear up some misunderstanding.
First and foremost as mentioned by Steve Worrall, this is really going to be a rigging and prop issue. Here's why:
When a boat has a tendency to pull to one side or a list while at speed (leans to one side), that is due to a huge amount of torque from too high of RPMs, the prop biting the water and potentially a torque tab that is in need of adjustment as well. My guess is that when you are up on plane, the motor turns easier to one side than the other. This can be adjusted out by a couple of changes. First, check the torque tab to see if it is not way out of adjustment. If the motor turns harder one way, turn the tail end of the torque tab the same direction (harder to turn left, adjust the tail end of the torque tab to the left). This will help some, but it will not solve it all....I think this might be more due to your prop than anything as an incorrect prop can cause all kinds of issues which compound on each other.
Another wat to reduce torque is to raise the motor up out of the water a couple of holes. As backward as it sounds, moving the motor up will increase the amount the prop will slip in the water, which will also reduce torque since there is more air introduced to the prop. This will also help take care of excessive bow rise on hole shot as well, given the motor is trimmed in fully (which if tilt stop is in the lowest or next to lowest position on the transom bracket).
Moving the motor up also has another advantage for you as well...it will reduce the amount of porpoise in the boat unless there is a bigger prop issue, which I have a feeling you have here. I'm guessing you get a big porpoise when you try to trim up (in other words, the boat will not trim well and the bow stays down), which seems to describe the "digging" you mentioned. the prop does not match the set up..
Trim is the interesting part of the equation as the motor's ability to keep the bow up is dependent on RPMs, prop design and prop diameter. The lower RPMs, the tougher it is to keep the bow up, thus, when slowing down, one must trim down as well to keep the boat comfortable to run. If the prop is too high of pitch, porpoising will happen because the motor cannot reach full rpms...or...it can also happen because the prop DIAMETER is too small, the motor over-revs which means it is not grabbing the water well enough (which is what I think might be happening to you) when you trim up, thus the bow falls and the process repeats.
As Steve mentioned, your issues are most likely related to a prop, so If you are willing to divulge some information there, we might be able to get you onto something that will work much better. For starters, what props have you tried, and what what are your speeds with those props? Brand/model , pitch and diameter are important here as well as your rpms. If anything we can get you on a starting point to solve the issues. by the time it is all said and done, your boat will float along while cruising, knock you back when you throttle hard, and corner well, without any undo stress on you, or your boat.
Steve
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Posts: 29
| Thanks for all the input guys, I think we are getting some where. As to answer some questions I went from a Suzuki 21 P to a 23 P then to a 25 P prop, the diameter I do not know. The the torque tab? The trim tab has been adjusted far right to get this situation alot better. Now as far as rigging, the motor is as far down as it an go otherwise the steering would hit the fiberglass. It makes perfect sense to me that I will need to raise the motor up one notch to resolve the propoisingand maybe lean issue. Now when we talk of torque of the motor more torque would make the boat lean more right, so it is issue of not having enough? After the fact maybe put a 27 P prop on to resolve the rev limiting issue. Let me know what you think of my assessment or what route I should go. Thanks Matt
Edited by Apex 12/11/2012 9:52 PM
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Posts: 3488
Location: Elk River, Minnesota | Hi Matt,
First and foremost, finding out the diameter will be a big issue here. With the selection of props out there to choose from, you could quite easily change close to a full inch in diameter, which would equate to roughly 400 rpms in the same model of prop, and significantly affect the handling of the boat. So..before changing out a prop, let's get that figured first.
Second, if you are running a steel prop (which on that rig I would HIGHLY recommend) that motor can probably come up to the third or even the 4th hole depending on how tall the transom is to begin with, and whether or not the transom has a setback as well. Gut instinct tells me you can go up all the way if you run a good aftermarket steel prop. If you are running aluminum, the best you might be able to do is up two holes...after that, the prop will blow out.
On that rig, though...a good steel prop will be a good thing for handling, overall lift (both bow and overall) and it will help an over-rev as well. On a big V-6 like that, steel most definitely will out perform aluminum.
One thing with torque...if you cannot trim up, that torque will be excessive...when you trim up, torque is usually reduced tremendously as well.
Rev limiter is what rpm on that motor...6500? Also, what kind of speed were you seeing at that point? Establishing a baseline is what is needed....then from there, we can start the plan to change things.
Steve |
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Posts: 29
| Thanks Steve, sorry to over think the porpoising issue it. I can only run a SS prop on this motor. At 6500 RPMs I am seeing 55 MPH. Will get the diameter to you 2morrow. And just so I understand the prop running right at or below the hull will help with over all performance? |
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Posts: 3488
Location: Elk River, Minnesota | Hiya,
In most cases when a dealer sets up a rig, they set it up so the cavitation plate is level with the lowest portion of the hull. But..that is a position designed for overall handling with an aluminum prop and for acceptable speed as well. It is by far from the most efficient set up.
In your case, and running steel, the boat will perform much better when the motor is higher off the transom. In many cases, the cavitation plate can be as much as 2 inches ABOVE the lowest point on the hull. This is due to the boat making a "hole" in the water, so when the boat passes over, the water starts to fill the hole. I happen to run a tin boat, but I added a 4" setback plate on mine, which allowed me to raise the motor even higher (with a water pressure gauge) to get every bit of performance I can out of the boat.
An ideal set up has the cavitation plate just above the water line when the boat is on plane and trimmed (you can check this if you have a partner in the boat who can either take the wheel or peer over the back end as you go) If the plate is in the water, the motor in most cases is too low. And...with a good steel prop, that plate in the water will only slow you down. The prop will grab plenty of water for handling and turning, although you will (and should) trim down in moderate turns so the boat helps carve the turn and the prop continues to grab.
I wouldn't say you are over-thinking things...just processing what is going on. THAT is a good thing...
Steve
Edited by VMS 12/12/2012 11:37 AM
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Posts: 5874
| Suzuki's have very high numerically ratio gearing. In your case, you have a inline 4 cyl, with a 2.50:1 ratio. To compare, a Merc 150 4S has 1.92:1 and Yamaha has 2.00:1. Big difference when it comes to propping.
Here's a list of the available Suzuki props for your motor. Hard to believe you are over-revving a 25P, unless the diameter is smaller than the 14 1/2" as listed below. How far are you trimming it out when over revving?
DF150/175
Type Material Blades Diameter Pitch Part Number DF150/175
150-175 Stainless Steel 3 15-1/2 17 990C0-00830-17P n
150-175 Stainless Steel 3 15-1/4 19 990C0-00830-19P n
150-175 Stainless Steel 3 15 21 990C0-00830-21P n
150-175 Stainless Steel 3 14-3/4 23 990C0-00830-23P n
150-175 Stainless Steel 3 14-1/2 25 990C0-00830-25P n
150-175 Stainless Steel 3 14-1/2 27 990C0-00830-27P n
150-175 Stainless Steel 4 14-3/8 23 990C0-00834-23P n
150-175 Stainless Steel 4 14-3/8 25 990C0-00834-25P n
150-175 Stainless Steel 4 14-3/8 27 990C0-00834-27P n
150-175 Stainless Steel 4 14-3/8 28 990C0-00834-28P n
150-175 Stainless Steel 4 14-3/8 29 990C0-00834-29P n
The Merc REV 4 is a big prop and has a 14 5/8" diameter by comparison. |
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Posts: 29
| Hey Steve,
I uploaded some photos, the one of the tape measure is showing the hull at 17 inches. might have to go the full 2 holes up!?
Attachments
----------------
 Hull.JPG (48KB - 221 downloads)
Hull 2.JPG (53KB - 194 downloads)
Hull at 17.JPG (49KB - 188 downloads)
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Posts: 32901
Location: Rhinelander, Wisconsin | You are already two up. I wouldn't raise it any more. Look at the cavitation plate and see if it's above the running bottom at center keel. |
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Posts: 3488
Location: Elk River, Minnesota | Hiya,
After the pictures, I think you might be a tad high for the motor unless you get into a highly raked and highly cupped prop. I don't think going up is the answer either.
I'm curious about a question Shep posed as well..at what point do you stop trimming up? If you over-trim, the porpoising could be happening as you are over trimming and the prop cannot hold it, thus the front comes down...
wish you were closer and we had open water...I'd jump in with you to see what we could find out...
Steve |
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Posts: 29
| While getting to plane I have the trim all the way down in which it will dig and lean very hard to left once planned . I have to trim up half way (on my trim gauge) once on plane to get the boat level. Any sort of waves is where I start to have any issue as far as propoising, digging and leaning to the left very hard. Throttling it hard will correct and messing with the trim ALOT is the only way to fix it esp. the jump. WOT w/ trim up and letting on and off the throttle hard it will take on anything but my passengers are not very happy with my driving. Might have to get you guys in my boat to figure it out......... |
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Posts: 333
Location: menasha wi 54952 | What is the recommended HP rating for this boat (21' or 18') and how much gear do you have in it? |
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Posts: 3488
Location: Elk River, Minnesota | From what I have been able to find he is at max HP (going off of 2007 triton brochure).
I'm also curious as to where the gas tank is in the boat (more aft or more toward the bow...that can play a big role)
Steve |
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Posts: 3488
Location: Elk River, Minnesota | Hiya,
Can you take a picture of the lower unit standing behind the motor and submit? And...a close up picture of one of the prop fins?
The excess torque you are feeling I am betting is from being trimmed down, which is forcing the boat into the water, thus the pull and the lean (lots of HP will do that....it's like revving a good old muscle car and watching the entire vehicle tilt just a little to one side). Does that torque and lean go away to some extent when you trim out?
What I am curious about is the amount of cupping the prop has and the location of the torque fin on the bottom of the cavitation plate. If there is little to no cup on the prop, the prop is not able to grab the water well enough to hold the bow up...thus the porpoising. Trimming the bow should happen easily...if you have to trim half way through the trim range, the prop is not grabbing. The torque tab, if turned too much to one side, forces the boat to want to turn in the direction it is pointed...and you are constantly having to keep on the wheel to keep it straight. THAT can be adjusted out to some extent.
One thing to keep in mind is that stock steel props will perform quite similar to stock aluminum props as they have the same design, with the only difference being durability. I think you can get a better performing aftermarket propeller rather than staying with suzuki.... A stock steel prop will not usually allow you to raise the motor much off the transom either, although it will grab the water better than an aluminum. I wonder if your prop is ventilating which is leading to the rev limter...(Shep's thought there...)
Many aftermarket propellers will wake a struggling boat up due to various characteristics: higher rake angle, more cupping, blade design, adjustable vent holes, etc. which allow you to customize your ride to the qualities you want. Some people like a quick hole shot, while others look for flat out speed, and yet others want easy handling qualities throughout the trim and rpm range. A stock steel will not have that adjustability.
So...if you can find a dealer demo prop program in your area, you can try out different brands and styles of propellers to help you narrow down which one works best.
Couple of recommended props to try: OMC raker (if spline fits...Im guessing you have a 15 spline shaft), Michigan rapture or ballistic, or...even some possible mercury props with the exchangeable hub system in them...I'll bet there is a better prop out there that can address your issues.
To me, it sounds like you not only need bow lift, but entire boat lift...a good raked and cupped prop will do that...the OMC raker fits that bill well and you can find plenty of them on ebay, given your spline count will allow the prop to fit.
Steve
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Posts: 29
| Just an update. After contacting numerous prop companies and researching other Triton 177 issues. I was in touch with Solas (World wide company makes props for everything if you don't know of them) and got a good explanation for my problems. Their engineering department is suggesting me to not go to a 4-blade, not a higher pitch prop but a higher diameter prop. From my 14.5 to a 15.6. Their comments, "You will have better bow lift and won’t have to trim so high eliminating proposing" and "You may lose 1 to 2 MPH as the RPM’s come down". Seems like a legit diagnosis. Dodn;t get a exact reason or understand why a diameter change will help. Let me know what you think. Thanks Matt |
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Posts: 3488
Location: Elk River, Minnesota | Hiya,
What a diameter change will do for what they are recommending is to increase the contact area of the prop fins with the water. With more water contact, you gain friction between the water and the blade (this causes the rpms to go down) but that friction also means the prop will stay "hooked up" better in the water, resulting in the prop having a better ability to hold the bow up with less trim angle.
No matter what, I'd suggest getting out on the water with a bunch of different props in combinations of diameter and pitch. Spend some time making runs, turns, etc and see which one does the best job. Then...start playing with motor height. For some people, they enjoy this type of work...others, not so much... In the end, though...you will be much happier since the boat will perform the way you'd like it to..
Steve |
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