does anyone have experience with a newer 15hp suzuki

[DenisD]

Boater, I had a 1999 Suzuki 15 4-stroke on a 1448 MV Polarcraft that was built lake a tank and it pushed it very well, never clocked it for speed but I would guess mid 20s. This winter I got a 2009 Suzuki 15 electric start to mount on my 1436 Lowe. Sound familiar? Any way I have been waiting to post a reply because I had not run the motor on the boat. I ran it twice last week and am very impressed. I first ran with the boat fairly light, 3gal of gas, small lawn mower batt, empty live well, two mounted seats. The boat was a little heavy in the back and porposed some. I could not run wide open as motor would overrev. If I held revs to 6k I was running 23.5mph on GPS and had almost a quarter turn on throttle left. If I gave it full throttle I could get 25.5mph GPS before hitting rev limiter.
The next test was to take boat out loaded the same plus I added 63lbs. of lead to simulate flooring deck and trolling motor and gear. The boat rode smoother but motor but motor would still overrev as before, so the weight did not slow it down any that I could tell.
As far as torque for this motor I took the weighted boat from idling in gear to hitting the rev limiter in under 10 seconds, one time I think it was more like 7 seconds.
My plan is to change props from a 9 pitch to an 11 pitch and hope that's enough because that's the most pitch I can find for this motor.
I am thrilled with this motor, my electric start model weighs 105lbs and I can still pull start it if I run the batteries down.
I hope this helps you, I went through the same thing as you when I was choosing my motor.
DenisD

 

[bassboy1]

General rule of thumb is 1 inch of pitch equates to around 200 RPM, either way, give or take a hair.

If they were propped correctly, I don't think the gear ratio would make much difference. Now, by propped correctly, I do not mean the same pitch on both boats, but the pitch that is optimal for that boat/motor combo. In theory, the motor geared lower with a greater prop pitch will perform the same as a higher geared motor with a lesser pitch.

 

[bassboy1]

if they proped them all different it would never work.

Which is exactly why these tests can be misleading. It is darn near impossible to get an apples to apples test when different companies have different variations.

U may be right with the gear ratio but i can't buy it because if one has a better gear ratio it will out power/torque the other motor almost everytime.

Look at it this way. Lets look at lifted pickups with larger tires (not sure if that is as big a deal down there as it is 'round here). When you put the larger tires on the the truck, you are in essence gearing it up. Now, in order to keep the truck from being a real dog, new gears with a much lower ratio are often installed. This brings the performance back to right about that of the stock truck. Therefore, in a head to head race, not much is different, even though they have a difference in gear ratios. It works the same way on the boats, for the most part. Think of the prop as the wheels. In order to be the same, the lower gear ratio has to turn a greater prop pitch. But, because it is geared lower, it is able to turn that larger pitch without extra effort, the prop will just be spinning at a lower RPM. Since the prop will cover more distance in each rev, it equals out.

This goes right back to my comment on it being near impossible to make an apples to apples comparison. Because the gearing is different, identical pitch props aren't fair. With identical props, one motor is going to run out of power, and one is going to run out of revs. But on the other hand, putting different pitch props on isn't really "fair" either, so making a fair test just can't happen.

 

[DenisD]

Well thanks on the info the guys at online outboards said the tohatsu 15 blew all the 15hp competition away in a test besides the merc which is the same motor they did for themselves so i can imagine what kind of power the tohatsu has.They also said the suzuki is a great motor to as they sell them to so they were not partial to the tohatsu just telling what there tests told them and that was against the honda 15hp,yamaha 15hp,and 15hp suzuki.

They tested all the motors against eachother and the tohatsu/merc beat all of them in top end speed,and power.Now this is what they told me and it kinda makes sense because the tohatsu has the best gear ratio at 2:15 and the other 3 are 2:08 which means that the tohatsu/merc is geared better.

But i would think any of them would scoot our boats.So if u had the proper prop what do u think your top speed would be around 30mph or close to that?Keep as much info as possible i like all the great info the more i know about this motor the more i want it.So the torque was good in the takeoff you were saying to.Maybe if i weighted the boat down more it would not over rev as i want to put a full plywood floor5/8,fill the middle livewell up with ice in the summer for fish,2 more coolers up front so that might do the trick,let me know if u do more testing i love to hear all of it thanks.

Here is another thing to it comes with a 9pitch prop standard also.What was the rpms when u hit the limiter?I would think a 10pitch prop would do the trick or 10.5 pitch.well let me know what u do i'm curious now.

I think I was hitting the rev limiter around 6300rpm. This motor is not totally broken in, so I only ran it that high for a second or two. I plan to order a 9.25x11 prop this weekend. When I get the new prop it's back to the lake for more "tests" :wink: Hopefully my boat will be so fast I'll actually have time to fish :lol:

Something else to consider with businesses is that what they have in stock or make the most profit on is usually the best there is. :---)

 

[DenisD]

I have seen a lot of those video too. They were helpful. I will have the new prop before next weekend hopefully and try it Sat or Sun. I'm having a boathouse built at my house on Lake Gaston so I'm wanting to be up there as much as possible. Might be a good lake for the next Tinboats meetup, sorry for the shameless plug for my favorite lake.
Like I said before I went through the same thing on motor choices as you are going through now. I wanted as much hp as possible, but now I'm glad I went with the lighter 15hp Suz as those 1436 boats do not offer as much flotation as the wider ones. A 15" transom and a heavy 4-stroke some times spells trouble #-o

 

[DenisD]

I have not been able to get a delivery date on new prop yet. I'm still hoping by the weekend. I don't really even know where it's coming from. Anyway keeping fingers crossed [-o<

 

[DenisD]

Thanks for the rev limiter info. I have a Tiny Tach on the motor but I think I remember reading the display is not updated instantly, this makes me feel better about the 11" pitch. I still think it will pull to max rpms with the boat loaded normally.

 

[DenisD]

OK Boater here's what I got with the 9.25x11 prop. With the boat loaded the same as before with the 63lbs. of extra weight. I was turning 5930 to 5950rpms and going between 25.9 and 26.1 mph on GPS. This puts me in the correct rpm range for this motor. I also removed the extra 63lbs and ran between 27.1 and 27.3 mph while turning 6030 to 6050 rpm. The idle to top speed took around 15 to 20 seconds. I am impressed with how well a little 14 footer with a 15hp moves.

I also own a 1546 Alumacraft with a 25 v-twin Suzuki and right now I think this 14 would out run it. At least until I raise the motor, but that's another story.

I am absolutely thrilled with my Suzuki, but I also wonder how these boats would run with that 20HP Tohatsu, my other motor choice. If you are going to be carrying the kind of weight you spoke of earlier, 825lbs which is 150lbs overloaded, I don't know if you need a lighter motor or more powerful one. Good luck and let me know what you get and how it works. DenisD

 

[DenisD]

Congrats on the weight loss. Remember with our size boats losing 63lbs will get you over a mile per hour in top speed =D> . My boat was not as fast out the hole with the new prop, but that's to be expected. It did jump on plane quick and pulled hard all the way to top speed. As far as running 27mph, the boat handled it well. I did have to slow way down crossing boat wakes as the boat felt like it could catch some air. I have to remove my motor when not in use so the weight difference between the Suzuki and Tohatsu was important. The Suzuki can still be a handful to manhandle on and off the boat if I'm tired. I'm looking forward to hearing about your new motor.

 

[DenisD]

Sorry for the post delay been a little busy. I saw you were getting opinions on oil mix so I'm guessing your sale did not work out. I wouldn't sweat it you have a great little motor there. I still want to hear about how it moves your 1436.

 

[Pappy]

All of the original 4-stroke OMC/BRP engines in that horsepower range were Suzuki based. They ran well, started well, and did everything they were designed to do. Worked on one today, a 2004 model, that has had little to no maintenance and other than needing a carb cleaning the engine still performed well, started on one pull (after the carb job) and ran great.