Boat/Motor Compatability

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elh79

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I just acquired a tracker grizzly 1548 hull. It is rated for a 40 horse max. I also have a 70 horse 1975 Johnson. Barring it being illegal or not, do you think this combo will work? I know today motors are rated differently than yesterdays. It is almost twice the rated HP. What do you guys think? Will it work?
 
JB

JB

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Re: Boat/Motor Compatability

It would probably work if it didn't pull the transom underwater.

But it would only work until it killed you or somebody else or scared you so bad that you took it off.
 
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elh79

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Re: Boat/Motor Compatability

So you think a 40 horse from today is still less powerful than a 70 from 1975? I figure the weight difference wouldn't be much different between a 70 2 stroke and a 40 4 stroke. But again I don't know a whole lot about outboards.
 
tashasdaddy

tashasdaddy

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Re: Boat/Motor Compatability

your 70 weighs in at 210lbs the 70 is probably equal to a 60.today.
 
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elh79

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Re: Boat/Motor Compatability

Looking at some of the engine manufacturer websites: Evinrude 40 weighs 240lbs. Mercury 4 stroke 216. If you are correct about my engine weight will not be an issue. Overpowering the boat will be.
 
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elh79

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Re: Boat/Motor Compatability

correction the evinrude 2 stroke only weighs 109 but the mercury 4 stroke 40 weighs 216
 
jtexas

jtexas

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Re: Boat/Motor Compatability

Is that a 15 foot boat? How wide? 6 feet or so, should be ok. Less than 5 feet, no way. Get a couple guys to sit on the transom, see how it floats the weight...nadaguides.com will give ya the weight...would've guessed more than 210 but I don't doubt tashasdad

just my 2¢

curious...in 1975 that motor made 70hp at the powerhead...30 years later...wonder how much power it makes today...
 
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elh79

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Re: Boat/Motor Compatability

Thats what i was thinking. the motor has prolly lost some power from wear although it runs good. Also HP is now rated at the prop. The boat is 48" at the bottom. The rest all the way up to 20 ft are only 6 inches wider. I'm not sure how wide at the top. Im trying to figure out if I need to trade this for a longer boat, or go for it.
 
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elh79

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Re: Boat/Motor Compatability

the beam is 67" is that the width at the top of the transom?
 
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elh79

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Re: Boat/Motor Compatability

I am betting it will work. just need some other opinions
 
jtexas

jtexas

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Re: Boat/Motor Compatability

elh79 said:
the beam is 67" is that the width at the top of the transom?
Click to expand...

Yup - beam supposedly means width at its widest point. 20-inch transom height, right?

disclaimer: I'm no expert, I've never attempted to do what you're attempting, I'm not advising you to do it, I'm not affiliated with iboats, yada yada yada. Presumably you've considered all the ramifications, legal moral & otherwise and paid up your life insurance. ;)

Bet it tops 55mph.......

On the other hand...I have a 15fter, and it gets pretty cramped for a day's fishing...sure would like to have another foot or two.
 
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elh79

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Re: Boat/Motor Compatability

well I will probably prop it down some also. I duck hunt a lot and 3 people, dog, gun, and decoys will slow you down a lot. I'm sure I'll be pushing max weight 75% of my time on the water.
 
tashasdaddy

tashasdaddy

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Re: Boat/Motor Compatability

do a seafoam decarb and pickup that lost hp. get the crud out of the engine.
 
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elh79

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Re: Boat/Motor Compatability

Well I guess we will see this weekend. I can always take it back off. I know there is someone out there who has done something like this, or maybe they didn't live to tell about it...lol
 
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Rancherlee

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Re: Boat/Motor Compatability

My 16 foot is rated for 75hp MAX and my Grandpa had a 130hp yamaha on it from 1987 (NEW) to 2004 when he gave the boat to me. He kept the 130 and gave me a 55hp he had sitting around. The boat handled great and would top out at 60mph, actually he said he prefered the way this boat handles compared to his 18 foot 190hp I/O glastron at WOT (which chinewalks at 45mph). Like others said, you won't know until you try it.
 
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jaymasta

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Re: Boat/Motor Compatability

my cousin put a 40hp on a 15ft aluminum fishing boat with bench seats and it was rated max 25hp, he did it becuase he was always pushing max weight, porpised like a ***** at WOT and he would usually have to shut it down but the thing flew even fully loaded, remember you dont ALWAYS have to go WOT, the extra powers there just in case LOL
 
deejaycee_2000

deejaycee_2000

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Re: Boat/Motor Compatability

jaymasta said:
my cousin put a 40hp on a 15ft aluminum fishing boat with bench seats and it was rated max 25hp, he did it becuase he was always pushing max weight, porpised like a ***** at WOT and he would usually have to shut it down but the thing flew even fully loaded, remember you dont ALWAYS have to go WOT, the extra powers there just in case LOL
Click to expand...

My 2.6meter inflatable is rated max 5hp, i'm installing my new 70hp racing motor this weekend ..... the modified 30hp is too slow ......
 
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