What 4-stroke should replace a 15hp 2

goodvibes

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Dec 15, 2010
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Hello everybody. I have a 12' aluminium gamefisher with a 15hp 2 stroke, also a gamefisher. I am wanting to switch to 4 stroke for cleaner and quieter running. The gamefisher motor weighs 66lbs. From the specs i've read about most 4 strokes the 9.9 is about 92lbs and the 15's are around 115lbs. It seems the 9.9 might not be enough motor @ that weight, but the 15 @ 115lbs might not do well on this hull:confused:Thank you for any info
 

dboyd351

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Nov 7, 2010
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Re: What 4-stroke should replace a 15hp 2

Would certainly be beneficial if you could test run it. Any way you could get it from a dealer who would let you swap if you got the wrong one? Know someone who has one? How about renting one on a similar boat at a lake?

9.9 is the cutoff point on a lot of lakes. You might even go down to one of those lakes and see if there is someone who can answer your questions or give you a ride.
Good luck.
 

goodvibes

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Dec 15, 2010
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Re: What 4-stroke should replace a 15hp 2

Thanks, these are great ideas. I did not know that some lakes were restricted to 9.9. That may be the answer to my situation, because I want to travel across country with it. I'm using it now in the intracoastal, and more hp seems like it can't hurt. Except my back, which if the 9.9 will do a decent job then 90 sounds alot better than 115. Thanks again
 

robert graham

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Re: What 4-stroke should replace a 15hp 2

It would all depend on how far and how fast you want to go, but the 9.9HP 4 stroke would be fine for fishing lakes, ponds, creeks, rivers. Some of the newer 2 strokes are pretty quiet, efficient and light, so maybe think about that and the weight issue? Good Luck!
 

bassman284

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Jun 24, 2006
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Re: What 4-stroke should replace a 15hp 2

Looking over the mfgs' websites, it looks like 4 stroke is your only option if you're buyng new. The only 2 stroke I found was the Evinrude 9.9 HO at 186 lb (yikes!). Some of that weight is power t&t but still... Mercs 2 strokes bottom out at 75.

I checked Evinrude, Merc, Yamaha, Tohatsu and Suzuki. Might be another brand out there I haven't thought of.
 

pecheux

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Re: What 4-stroke should replace a 15hp 2

IMO there is no replacement available to match a 15 hp OB at 66 pounds.
 

Whoopbass

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Jun 29, 2006
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Re: What 4-stroke should replace a 15hp 2

A new 9.9 motor will have plenty of power for your Gamefisher boat. I wouldn't be surprised if you get a higher top end speed out of the 4-stroke then you are getting out of your 15hp Gamefisher.
 

pecheux

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Re: What 4-stroke should replace a 15hp 2

A local BRP dealer salesman told me if I wanted the same power as my Johnson 9.9 hp 2 strokes I would have to buy one of their (then available) 15 hp 4 strokes to match it. But I did not buy it mainly due to not wanting the weight of that OB on the transom, so I'll never know for sure.
 

javsam

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Aug 24, 2005
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Re: What 4-stroke should replace a 15hp 2

Yes I also agree IMHO,that there is no replacment for a 15 HP outboard weighing only 66 pounds,I have one of those lightweight outboards and the weight is actually 58 LBS.
The newer Four strokes are very heavy. 115 LBS =my aching back.
 

goodvibes

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Dec 15, 2010
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Re: What 4-stroke should replace a 15hp 2

In my internet travels to research motor options I've come across some electric options. Youtube has several people using outboard lower units with electric motors as the powerheads with impressive results. Of course there is the weight of the batteries, but I can place some in the bow where I need some ballast when solo. Has anyone here tried anything like this? I have some parts already to get started, and I think I can buy the rest @ prices competitive with gas units. :cool:
 

javsam

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Aug 24, 2005
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Re: What 4-stroke should replace a 15hp 2

Why not keep what you have,which is a lightweight package and try to get your outboard running cleaner by first doing a Decarb on the motor. Then try switching over to a full synthetic TCWIII outboard oil (penzoil full synthetic is a good one).And finally if the noise is bothering you, have you experimented with any sound deading insulation inside the hood?
 

JRJ

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2,992
Re: What 4-stroke should replace a 15hp 2

I had a 15hp Johnson 4 stroke for a kicker. For the weight and thrust, I'd seriously look at a 6hp next time. All depends on what you want to do.
 

Expidia

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Aug 26, 2006
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2,368
Re: What 4-stroke should replace a 15hp 2

I have a 2007 9.9 Merc 4 stroke which I bought new. I had it on a 13 foot Aluminum Sylvan Alaskan Deluxe.

A 9.9 will do you fine. Will go a little slower with two people on board. 3 people and it really slogs down. When it's just you in the boat it will jump up on plane pretty quick.

For those times you want to fly across a lake (like when a thunder storm is coming) I had on board one of those aluminum throttle extension handles http://www.sears.com/shc/s/p_10153_...19x00001a&ci_src=14110944&ci_sku=SPM597876401 and I'd extend it so I could sit on the middle seat and I'd skim across a flat lake around 20 MPH to get back to the dock. They can be found for around $20.

I used to leave mine on the boat while trailering and used a transom saver and a bungee cord so it didn't bounce up and down while driving. Due to their weight they are not that easy to pop in and out of a trunk or truck when you are alone.

Also, remember unlike 2 strokes, they have oil pans in them and you can only lay them down in trunk or truck facing with the correct side up or oil will spill out. I learned the hard way when I let this kid at the dealership put it my trunk without watching him. Was a mess when I got home :eek: luckily I had it laying on a big plastic garbage bag.
 

pecheux

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Re: What 4-stroke should replace a 15hp 2

Just like expidia I also use a tiller handle extention on a 12 F allu + 6 hp motor and sit on the middle seat. By doing so it will run at surprising speed to get me to my fishing point. This system improves speed on most boats.
 

Home Cookin'

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Re: What 4-stroke should replace a 15hp 2

I find this hard to believe: A local BRP dealer salesman told me if I wanted the same power as my Johnson 9.9 hp 2 strokes I would have to buy one of their (then available) 15 hp 4 strokes to match it.
I mean, I believe a salesman would say it but I don't believe it's true!
other than environmental concerns, I can't see the 4 stroke's advantages outweighing the 2 stroke's advantage of being (a) lighter and (b) already bought and paid for. On a 12' jon, that transom weight is very important.
And why would there be PTT on a motor as small as a 9.9? That sounds excessive, too. But I hear they even make electric start 9.9's, which is also excessive IMO.
 

Expidia

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Re: What 4-stroke should replace a 15hp 2

And why would there be PTT on a motor as small as a 9.9? That sounds excessive, too. But I hear they even make electric start 9.9's, which is also excessive IMO.

I would think someone who was using a 9.9 as a kicker on a bigger boat, would benefit by PTT.

2 stroke or 4 stroke a 9.9 starts pretty easy, but if I was leaving the O/B attached to my boat anyway and had a battery onboard for lights etc and I had a choice of two O/B's or my Wife had to start it on occasion . . . these old bones would snag the one with electric start :D

To the original poster . . . Using an O/B handle extender is sweet, but beware that you lose a fair amount of control and the quick handling characteristics of being back in the stern right next to the O/B. I've had some close calls when sitting in the center seat at full extension, flying across the lake and hitting a wave. I would not let my kids use an extension or down a few beers and take off.
 

LonLB

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Nov 19, 2010
Messages
264
Re: What 4-stroke should replace a 15hp 2

I find this hard to believe: A local BRP dealer salesman told me if I wanted the same power as my Johnson 9.9 hp 2 strokes I would have to buy one of their (then available) 15 hp 4 strokes to match it.
I mean, I believe a salesman would say it but I don't believe it's true!
other than environmental concerns, I can't see the 4 stroke's advantages outweighing the 2 stroke's advantage of being (a) lighter and (b) already bought and paid for. On a 12' jon, that transom weight is very important.
And why would there be PTT on a motor as small as a 9.9? That sounds excessive, too. But I hear they even make electric start 9.9's, which is also excessive IMO.

The PTT, and electric start is for using the engine as a kicker.
Some now are being offered with heavy duty transom brackets, high torque gear cases that handle larger props, and electronic throttle controls to make TINY adjustments in throttle, to make TINY adjustments in trolling speed.

These motors are built just for use as kicker motors, and would be a waste of money and weight on a small boat.
 
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