Horsepower degradation

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Horsepower degradation

Postby skanders01 » Sat Sep 22, 2018 7:29 am

I tried a couple of searches but could not find the magic search words. I am trying to decide between two motors. One is a '79 35 HP Evie and the other a veritable newborn...a '92 30 HP Evie. Both gave average compression for their age. Not that 5 HP will make that much difference, but it made me think about my selection process.

The question I have is a basic one. is there truly still a 5 hp difference between these motors (other motors) how does HP degrade with age? Has any quantitate research ever been done?
Kyle Anderson
DePere, WI

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Re: Horsepower degradation

Postby FrankR » Sat Sep 22, 2018 8:17 am

If you are trying to decide which motor to purchase, get the '92. The '79 35hp motors had cooling problems. That far outweighs worrying over that little 5hp. Just my 2c

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Re: Horsepower degradation

Postby destroyer85golf » Sat Sep 22, 2018 8:27 am

I would think that you are probably right on about the 5 hp difference not bein noticible. But what about the weight difference? I wouldn’t think there would be that much degradation. It’s just my opinion, but you can draw a parallel between compression and horsepower, if the 79 has good compression, I doubt it has lost much power.

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Re: Horsepower degradation

Postby Kerry » Sat Sep 22, 2018 8:42 am

The '79 is crankshaft rated, the '92 is propshaft rated. I'd call it even.
If you have too many, AND not enough, you are a collector!

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Re: Horsepower degradation

Postby Chris_P » Sat Sep 22, 2018 10:01 am

As stated, you would NOT be able to notice any difference. Buy the 92.

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Re: Horsepower degradation

Postby reivertom » Sat Sep 22, 2018 3:34 pm

Kerry wrote:The '79 is crankshaft rated, the '92 is propshaft rated. I'd call it even.


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Re: Horsepower degradation

Postby outbdnut2 » Mon Sep 24, 2018 9:52 am

The '79 will not run well at slow speeds just a bit above idle. All motors have a rough throttle spot where the carb is going from lo to Hi jet, but on the '79, this rough running area is a wide throttle range - irritating for loafing along on a pontoon or any other boat at a few MPH.

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