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| New Tuffy 1700, 115 Optimax. Mercury Black Max, 17 pitch.
Initially, the trim/torque tab was mis-adjusted. The boat pulled hard to the right and leaned hard to the left. During that time I achieved 5400 RPMs and 40 mph.
I re-adjusted the trim tab (trailing edge rotated from left of center to equidistant to the right of center), and now the boat runs straight and level - phew. However, I had the boat out with just myself and got 5200 RPMs and 38 mph, and with two people, it was closer to 5000 RPMs and 37 mph.
Engine is mounted with one hole above the bolts, and will usually be run with one person, occassionally two, and rarely three people.
So, any advice on what prop I should be running/trying?
Thanks!
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Posts: 25
| I'm going through the same thing right now with my 115 etec. The cheapest place to start is to make sure your motor is at the right height on the transom. If it's similar to other motors you want your anti cavitation plate riding a little above the water at WOT when properly trimmed. This is easy to do yourself in your garage with your trailer. Took me about 15 minutes to raise mine 2 holes. Looks like your motor wants to be about 5700rpm at WOT so you might have to change props once you get your height set, but I would work on proper height first and go from there. | |
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Posts: 395
Location: NW WI | Have you asked your dealer for help? | |
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Posts: 32884
Location: Rhinelander, Wisconsin | The height is correct. You are running an aluminum prop, and can expect about the performance you are getting with that blade. Is the motor fully through the break in period? If not, I'd wait until that's completed before adjusting for prop pitch. | |
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| Thanks!
skis - Dealer is helping. He said he'd get a couple of different props in the range we want and has offered to come to the water and try a couple out.
sworrall - I think the break-in is about done. Is there an hour meter that I can read, or does it have to be checked by computer? After talking to Mike this morning, I trimmed up a little more aggressively, and got to about 5500 RPMs with just me in the boat. Am I understanding correctly that a stainless prop is thinner, and will therefore spin a little faster? What other advantages are offered by a stainless prop? Might I want a 4 blade? Lastly, rumor has it you're running a very similar set-up this year - can I ask what prop you opted for?
Thanks again. I love the boat, and it even catches fish! No muskies yet, but all in good time! | |
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Posts: 395
Location: NW WI | Steve is right in that you want to make sure the motor is fully broke in before you try different props. Unless you had an hour meter installed, a computer hooked up to the motor will be the only way to check the hours. You did break the motor in properly right?
To get the best performance, spend the money on a stainless prop. Your dealer can recommend the correct series of Merc props. Make sure you get the motor RPM's at or near the max rated for the motor with a typical load in your boat.
Trimming the motor = how I do it is to get to the cruising speed range you want to be at, trim the motor up until you see your RPM's start to rise quickly...that means the prop is starting to cavitate...then go back down on the trimp just a tad.
Enjoy the new boat....sounds like a sweet rig!
Edited by Ifishskis 6/6/2010 5:47 PM
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Posts: 3480
Location: Elk River, Minnesota | Hi Everyone,
After the motor is broken in, I would say that if you try a steel prop, you can raise your motor at least one bolt hole. Although one hole up is a standard height when the boat and motor are assembled, quite often it is not the most efficient placement of the motor. When assembled, motors are put on at a height that gives overall decent speed, and good handling. But...if you are looking for more, changing props and raising the motor can do wonders with a result of a great handling boat, good gas consumption, and excellent handling. If you stay with an aluminum prop, the height you have will be best. A stock aluminum prop has very little cupping and a bunch of flex, so keeping it deeper is what it takes to get acceptable performance.
Now...put a steel prop on there with some good rake and cup, you will have a prop that will not only lift the bow...it will lift the entire boat, resulting in less wetted surface and a faster ride.
You mentioned with some aggressive trimming you could get to 5500. I would assume this means you trimmed to the point the bow was porpoising or ventilation started? If not, you might have more trim to go, which will bring your RPM's up further. If that is the case, and without running or seeing the boat, I would bet you could get to a steel prop with about 2 inches less in pitch, and raise the motor 2 holes...all of this dependent on what prop you find that works best on your rig. If your dealer is willing to bring in a few different props for you to try, see if you can get them all at one time and head to the lake for some testing....chances are, one will significantly stand out as being the best in handling, lift, torque, and speed...THAT is the one to go with.
with any prop change, there are trade-offs as well. A prop designed for speed will not be as good on hole-shot, but a vented prop can curtail some of that issue, allowing the prop to slip a bit until there are enough RPMs to send the exhaust gasses past the vent holes....the prop will catch and pop you out of the hole.
Steve
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| Thanks all:
I followed the break-in, and am still avoiding long stretches at any particular RPMs. The manual says to change speeds every 2 minutes during the first hour, and every ten minutes for 3 hours after that. It also says that the "extra oil mode" will be over after about ten hours. I'm approaching ten hours, but probably just shy, and not sure exactly how many hours I've got. Is there a way to know when the break-in is officially finished?
I've been driving boats my whole life, but mostly inboards and/or small tiller outboards without power trim. This is the first new set-up I've had, and the first console (trim & tilt) outboard in about 20 years. It sounds like I could use some on-the-water pointers on trim adjustment, and that I'd like to try a steel prop. The bit about bow and boat lift sounds great. I originally ordered a steel prop, which my dealer said would have been a 17 pitch Mercury Vengeance, as that is what the dealer said "Tuffy recommends." It didn't (and still hasn't, as far as I know) come in, which makes me wonder if it's available at all. I'll trust sworrell that the motor is mounted in the right hole.
I'm looking forward to seeing what my dealer comes through with in terms of different props, and how that influences performance. I'd like to see a little more speed, not because I really need it, but because I was told it would be there. My real concern is for the motor, and whether I'm causing damage by running below recommended RPM's. I'll report here with results.
Thanks | |
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Yet another propping question