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Posts: 11
| Was finally able to take out my "new" boat. It has a 50hp Honda. It topped out at 24mph and 3200 rpms. It had a full tank of gas, 3 batteries, and about 300 extra pounds between my dog and I.
Is the top end about what I should expect? The low rpm's kinda worried me, but I don't have the owners manual for the motor to check what rpm's it should be running at. An aquaintance told me that 4 strokes run lower rpm's than 2 strokes?
Also, does anyone know a site where I could download the owners manual for my motor?
p.s. I still haven't found a kicker motor for it...so no extra weight there.
Tony |
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Posts: 437
| You can try here for a owners manual:
http://marine.honda.com/owners/manuals
Those RPMs do sound low, but I am not familiar exactly with that motor. The one I found said operating RPM full throttle should be 5500 to 6000. Though this may not be the exact year/model as your's, but something to definitely check on.
Edited by Captain 5/14/2012 1:02 PM
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| I have a 2001 Navigator 165 tiller with a 50 Honda... run top speed 25 mph with about the same gear as you, RPM's at full trottle 5500
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Posts: 3514
Location: Elk River, Minnesota | Hiya,
I would say you should probably see a bit more in both RPM and speed out of the boat. RPM's are well below max for that motor as the max RPM is 6000.
Right off, this tells me two potential areas to check: First would be the pole setting on the Tachometer as I think you are probably fairly close to your maximum speed with the boat. I would think close to 30 would be about right for that boat as it sits alone is 900 pounds alone before adding 23 gallons of gas. This is assuming you trimmed the motor up while at full speed. If you did trim up, then get the motor warm and running at idle speed. Determine what your RPMs are reading at idle and compare to the specifications for the motor. This might be a little fuzzy since I believe you can adjust the idle speed to some extent.
I am wondering, though, and am just going to throw it out there as a possibility...did you trim the motor up while on plane? If not, the 3200 RPMs would sound about right as when trimmed down, the bow is essentially being "pushed" into the water rather than being pulled up out of the water and the stern is being lifted. This would also account for the lower than expected speed. If this is the case, take the rig back out, trim in and get up on plane. Then, start trimming out until either the bow starts to porpoise or the motor does not gain any more speed, but rises in RPM. When you reach the point where either of the two scenarios happen, back the trim down just a touch and record that RPM value and the speed your boat obtains.
If the Tach is correct and you are trimming up, then I would be looking at a potential over-propped engine. If you can, take a look at the pitch and diameter of the prop as well...it is probably stamped on the side of the prop, or is located under the prop nut and washer. This can also tell a bit about the situation.
Steve
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Posts: 11
| Thanks for the responses everyone. I'll be out on the water this weekend and I'll be able to mess around with it. I'll let y'all know how it goes.
Thanks again!!
Tony |
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| Is your Navigator the older 84" beam model or the newer 90" model? Your 50 should be a near perfect match for the older model. I used to run a smaller Alumacraft 16.5'x76" beam Lunker with a Honda 30, and I dropped to a 10 3/4x 10"pitch prop for running with a load. WOT RPM was maxed at 6200 (digitally verfiied), but it jumpd out of the water like it had a 60 on it, and pulled big loads no problem. 4 stroke motors need to run near WOT to achieve best power IMO. WOT speed was about 26. With a light load and a 12" std. prop, I hit 28mph GPS'd.
Your boat (assuming it is the older 84" beam model), should hit close to the max 6,000 rpm if it is propped correctly, and you will not lose much if any WOT speed. You should be able to reach 28-30mph if it is propped correctly. There is a performance report of a shoot out of 50's a few years back and that Honda on the 84" beam hull ("now called "Classic") and w/ a stainless prop hit something like 34mph with 2 guys in the boat. I now run a new, 90" beam navigator w/ a 60 Yam. 4/s, and w/ an 11" pitch prop (Hustler) I run 30.8 mph (GPS) with a light load, and 28mph loaded. You may wish to play with the trim (just below cavitation under plane), and the mounting height of the motor. If you have that 50 on the 90" beam model, you are a bit underpowered, and will definately need a low pitch prop- something like a 10" pitch, and I would presume would top out at about 25mph at WOT.
I also wouldn't think you'd really need a kicker with that motor, as it should troll down nicely, and the extra weight of a kicker will definatley affect performance. A friend has the same powerhead in a 40 Honda on a very similar hull, and we troll all day no problems. |
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Posts: 437
| I was thinking the same thing about a kicker for that boat. Those little 4 strokes run so nice and troll down so well I wouldnt see it being necessary. I troll with my 150HP suzuki around 2mph. Throw a drift sock or one of those trolling control devices (cant remember what they're called) and you could get the speeds way down with a 50. |
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Posts: 3514
Location: Elk River, Minnesota | Hiya,
I personally will always advocate for a kicker motor, most notably for when going out on big water where if something happens to the main motor, you have a way to get back to camp or the launch. Much of that comes from being on waters where the nearest town is 17 miles (by boat) and rocks are not marked. I have seen on more than one occasion...more like 10 to 12 where one boat had to spend part of a week fishing using only a 6 or 8hp motor because the big one no longer had a functioning lower unit, or in one instance....no lower unit.
I once was about 10 miles from camp on the clearwater/pipestone chain when I tore out a lower unit on my 50hp. I was very glad I had a 6hp kicker along. 2 hours later, I was back home safe.
If I read the original post correctly, the boat is a 2005, which will be the wide beam, so there is plenty of room to put a kicker. I have an 8hp 4 stroke for mine, and can run both off of the main tank by installing a fuel/water separator which had 3 different usable fuel outlets. Made it nice so I didn't need to carry an extra gas tank just for the kicker. With the right kicker and prop, you can get down to right around or just below 1mph...very nice for walleyes or slow trolling spinner baits...
In my humble opinion...a kicker is priceless. Not needed on some waters depending on where or how you are fishing, but the bigger stuff....it's like they say with an american express card...don't leave home without it.
Steve |
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Posts: 437
| That is a VERY good point. A kicker is priceless when you need it, but you may not value it as much if you dont. It is always better to be safe than sorry. Thinking about it, if my big motor konked out in a blow on Mille Lacs, I would be screwed.
Will you help me convince my wife I need a new kicker? LOL I will say its "to keep the boys safe". That usually works. Or, I could just buy one and install it and just tell her it was always there and she didnt pay attention. 
I dont want to hijack this thread, but Steve, I had a question about setting up your kicker. You mentioned the fuel/water separator and just hooking up a gas line to it. Is it really that easy? For the fuel lines I mean. I have multiple outlets on my separator and just didnt think it would be that easy. If it is awesome! Thanks! |
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Posts: 3514
Location: Elk River, Minnesota | Hiya,
It really is that easy. All you need to do is run your main line from your tank on the boat to the fuel/water separator. Then, you hook your lines from the separator to the individual motors with a bulb installed on each line. The two motor lines are separate from each other and pull off of the fuel in the filter. It was much simpler than I expected and I have had no issues whatsoever with it. I think mine had two inlet plugs and two outlet plugs, so I had to plug the other inlet...but it is quite easy. Any hardware store will have the brass fittings for plugging, joining, etc. A good plumbers putty that is solvent proof is all it took on the fittings.
I also like the idea of having the water separator for that purpose only... I am not picky when it comes to the gas I use...the motors now are designed to run on ethanol, so I don't worry about gumming a system, but I do worry about the fuel's ability to attract water if left for a long period of time. If I can separate that out, it definitely is better on the engine and it gives a slight performance gain. Just make sure you dump the fuel in the separator before storage.
Steve
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| I have the navigator 165, 91 inch beam, similiar issues with porposing. You mentioned 11" pitch, what diameter? same 11"
I have the yamaha f60 on this boat, nice troller, gets me 29 mph. I do have trouble with the hole shot with 3 people on board. Currently running a 10.5", 13p aluminum off my honda 50, runs way better than the prop boat came with. The previous owner had a 9" 13p aluminum? WTF? anyway so I am interested in the 11"pitch prop you mentioned earlier. Can you let me know the prop you are using and how high your boat motor is mounted? Thanks |
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Posts: 144
| I run a Navigator tiller that was rigged with a Merc 50hp 4stk. My boat has the wider beam and it was under-powered with the 50hp motor. I went to 10 pitch Merc. "Black Max " prop. I would think Honda would have an equivalent prop. The motor was mounted all the way down. I got about 5800rpm wide open and a top speed of about 26-27mph with just me and my gear. I don't know how the Merc compares to the Honda as far as gear ratio, but i would think the performance numbers should be similar. You should be running a 10 or 11 pitch prop. With another person or two my top speed is reduced to about 24mph. I had bad porpoising issues with my boat. It made it almost un-usable. I solved that with a Sting Ray hydrofoil. The hydrofoil fixed the porpoising and helped the boat plane relatively well. It was a decent combo after that. I re-powered with a 60hp. 2 stroke. and the overall performance is much better.
Edited by pete619 7/9/2012 4:31 PM
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Posts: 3514
Location: Elk River, Minnesota | Hiya,
There is no doubt in my mind Alumacraft was very conservative when they put their hp ratings on the navigator 165....especially in the tiller model.
One issue I had with mine back when I first purchased it was that same porpoising issue. I had a 90hp yamaha on it (smallest 2 stroke 90hp made) and it was porpoising really bad. Took it back to St. Peter where I took it for a spin with one of the builders. The first thing he did was feel the edge between the back of the transom and the bottom of the hull. Found that the seam was hammered up a little much behind the rivet line, causing my hull to porpoise. You wouldn't think a little 1/2" wide section of a hull would cause so much issue...but it can.
What he did to my boat is he first asked me if I wanted to watch or not (some people don't like watching their boat take a little work that might not be so "professional looking". After I said I wanted to see what they do in case I need to do a little more or not, he took a 4" wide mason's chisel and a hammer and with a few hits along the back edge behind the rivet line, he wedged the seam open a little more, which settled the bow down tremendously. Problem solved. All I did after they wedged it is filled the seam with silver silicone which matched the boat perfectly...couldn't even tell they did anything.
Pretty cool thing if you ask me...to be able to tweak the hull to match the need without damaging it. Saved me from getting one of those hydrofoils on that motor.
Steve
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Posts: 258
Location: Mayville, WI | Steve,
Awesome info here! Quick question too; 09 navigator 165 w/ 75hp yamaha tiller and stock prop. Just over 37mph at WOT and roughly 5800 rpm, will a stainless give me any advantage other than looking cool? |
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Posts: 3514
Location: Elk River, Minnesota | Hiya,
you are right on the edge of where it can do some good. A steel prop will usually be made in a manner to have thinner blades, thus it will cut the water better than a standard aluminum. There is usually something to be gained, not only in durability but in handling as well. In most cases you can raise your motor a couple of holes to gain some rpms back.
in your case with the 75 tiller (four stroke?) , I would highly suggest the ballistic propeller. It will give you close to the same RPMs as your aluminum (at least that was the case on my yamaha 90 I had). If this is a 4 stroke, you are getting good numbers on that boat already. with my 90, it was a 38mph boat until I did a few tweaks to the motor with the help of hydrotec marine.
the ballistic is highly cupped, which is what allows you to move the motor up and not lose too much handling. I loved it on my 90hp.
my suggestion would be to find one to try in the same pitch as your current aluminum and see how it performs. I would not be surprised if you saw a couple mph increase in speed. And...if you can then move the motor up a notch or two, you might even get a 40mph boat. THAT would be a great performer out of a 75.
Steve |
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| I have a 04 navigator with a 04 yamaha 60hp tiller. I love the boat, stability is above average. Wishing to get a 70hp yamaha tiller (2012). How much more performance would I gain with the new motor?
Currently
1 person in boat 32 mph (gps) WOT, empty livewell, full gas
2 people in boat 29-30 (gps) WOT, empty livewell, full gas
3 people in boat, 26-27 (gps) empty livewell, full tank gas
3 people in boat, 24-25 (gps) full livewell, full tank gas
I had a Yamaha 11-3/8, 13 pitch, aluminum prop for the above tests.
I also changed the prop hoping for better hole performance and speed with a slightly lower pitch, it was a flop, I used a Solaris 11.5" dia. 12 pitch and it lowe4red all my stats by 3-4 mph on all ranges, poor choice.
Just curious, have you ever switched props on your 60 yamaha tiler? |
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