Outboard Motor Size

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Stef
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Location: NE Pennsylvania

Outboard Motor Size

Post by Stef » Fri Nov 14, 2008 10:45 am

I'm thinking of upgrading from my 1978 7.5 Merc. to a newer 4 stroke. What seems to be the motor of choice? High thrust prop? How light can I go?
Stef
Odyssey #146

Tom Elsen
Site Admin
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Post by Tom Elsen » Fri Nov 14, 2008 11:37 am

Hey Stef
It really depends on the water you sail.
We use a Nissan 5 (four stroke). 46 lbs or so. Love it. It's great for most inland lakes. I think I'd want something a little bigger in waves and/or strong crosswind docking maneuvers.
Best wishes,
Tom

Mark Gutteridge
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Post by Mark Gutteridge » Fri Nov 14, 2008 11:39 am

Stef;
On Hunting Party we use a Nissan 6 HP 4 stroke.It weighs appox 53 lbs.
It has lots of power ,uses very little fuel and has been very dependable.
I believe the class minimum is 4HP.Someone will correct me if I am wrong.
The nissan as with all 4 srtokes has to be stored properly or the oil will drain out.Also if it is stored with the power head in a downward position some oil will get into the cylinder and mess with the combustion computer.
Chimo;
Guts.

LarryE-old
Posts: 233
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Motor

Post by LarryE-old » Fri Nov 14, 2008 5:10 pm

I have a Tohatsu 6, 4 stroke. Bought it almost 3 years ago and its used almost every week, year round, in salt water.
Can't say anything bad about it, real important to store it on its handle.
I got the extra long shaft, for the same price of a long shaft, as thats the one they had in stock. The prop stays in the water, even in large waves, motors really sweet.
Purr-Fect
262

fleck
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Post by fleck » Fri Nov 14, 2008 11:01 pm

Stef,

The nissan, tohatsu, and Mercury , 4,5,and 6 Hp are almost exactly the same engines. Each is a 123 cc engine. The differance is in the carb. These engines with a power prop are really impressive. Almost all outboard engines are propped for a speed that is greater than you will use on any sailboat. They're build mostly for planning hull boats and dingies. The power prop is build to create max thrust at the speeds that the sailboat will use. It also has a much greater bite in reverse.

Anything more than the 6HP 4-stroke is, in my opinion, overkill. The extra long shaft would be the best. Especially for the waves that can roll into the PA side of Lake Erie.

Below is the text from an old post on the same subject (if you don't have it already):

I'd bet that the 4hp would meet any speed requirements. If not, here's even better news. The Merc/Tohatsu 4hp, 5hp and 6hp all are the same size motors (123cc). I'm pretty sure the jets in the carb are the only difference. I'm using the 5hp ( I wanted the external tank) with the 'power' prop and it works great, hull speed or better. Be sure the keep the mount as low as possible, the 'extra' long shaft would be nice. The power prop has a lower pitch and flatter blades. With it we were able to TOW an S2 10.3 doing 4-4.25 knots(flat water). Mercury part number is: 812951A 1 .
Bob Fleck
Horizon 484

LarryE-old
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prop

Post by LarryE-old » Sat Nov 15, 2008 6:57 am

I can back up what Fleck said about the power prop. After reading his post I ordered that exact part #, my original one had a slight bend.
Nice gain of low end power.
Purr-Fect
262

Stef
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Location: NE Pennsylvania

Post by Stef » Sat Nov 15, 2008 8:38 am

Thanks guys.
Yesterday I did notice that the Tohatsu/Nissan 4, 5 & 6 were all the same weight. Power prop sounds like the best idea. I never had my 7.5 merc wide open, maybe half throttle. So, it's a waste of HP.
I have 5 months to find a good deal on the 6 HP.
Stef
Odyssey #146

Pete
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Post by Pete » Sat Nov 15, 2008 9:34 am

The Tohatsu is made by Nissan. I believe they're exactly the same.

grandillusion
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Location: South Havenish

Post by grandillusion » Sat Nov 15, 2008 12:45 pm

there is an outboard motor store on ebay there like $1450 with free shipping outboardsonline, I want a new one and the tohatsu[nissan 6 is my choice but the evinrude 8 is still running great, less for the 2 stroke smoke and it uses a ton of gas
S2 7.9 216, H 16 80127, Star 6188

Bob Kirsten
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Location: Farmington Hills, MI

Hate to disagree with Bob, but......

Post by Bob Kirsten » Sun Nov 16, 2008 11:47 pm

Guys, We sail Lake Erie and Lk St Clair, and in big waves there is no beating a 10HP Honda 4. I had a good running 5HP 4 stroke on my J24 which was good most of the time, except in bigger waves and wind over 20Kn. I have never run with the prop you mention, which does sound interesting, and it might change a lot for the lower HP motors.

Bob Kirsten
DD Mau
@438
Bob Kirsten - DD Mau
North Star Sail Club, Michigan
robert_kirsten@hotmail.com

Stef
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Location: NE Pennsylvania

Post by Stef » Mon Nov 17, 2008 10:47 pm

Seems like there is more than 1 high thrust prop. available. They offer 3 sizes, 6", 7" and a 6" "elephant ear" prop, the later being considered the true high thrust.
Stef
Odyssey #146

Stef
Posts: 320
Joined: Thu Jan 15, 2004 9:40 pm
Location: NE Pennsylvania

Re: Outboard Motor Size

Post by Stef » Sun Mar 15, 2009 8:31 am

Got a motor.
6HP Tohatsu 4 stroke(Tohatsu makes Nissan & Merc). Ultra long shaft (25"), with high thrust prop and as a bonus it has a charging system factory installed, all for $125 more over standard. Free shipping and NO TAX except TN residents. Outboardsonline had the best deals, thanks Grandillusion.
The 4,5, & 6HP are all the same motor weighing 55LBS, different jets in the carb.
Stef
Odyssey #146

BarryE
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Location: Port Huron, MI

Re: Outboard Motor Size

Post by BarryE » Sun Mar 15, 2009 8:17 pm

I switched a couple of years ago to the Tohatsu 6hp four stroke; I sail out of Port Huron, Mi about 1 mile south of Lake Huron on the St.Clair river, river current can be 5+ knots at times especially right under the Blue Water Bridges, especially if there is a strong north wind behind it. So far no problems, even with the stock prop.
Engine replaced a worn out 82 vintage Johnson 10hp, 2-stroke. New engine is tons lighter, and feels like it has more thrust especially down low. (these are my impressions, I can't quantify this). I'll probably spring for the better prop before launching in May.

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