Horsepower degradation

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skanders01
Posts: 74
Joined: Sat Sep 10, 2016 10:47 am
Location: Green Bay, WI

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
920-532-6229
skanders@new.rr.com

FrankR
Posts: 3769
Joined: Tue Mar 10, 2015 6:32 pm
Location: Florida

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

destroyer85golf
Posts: 30
Joined: Tue Sep 18, 2018 8:33 pm

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.

Kerry
Posts: 308
Joined: Sun Apr 05, 2015 1:27 pm
Location: Grand Rapids, Mich.

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!

Chris_P
Posts: 2626
Joined: Tue Mar 10, 2015 4:59 pm
Location: Hamilton ON
Contact:

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.

reivertom
Posts: 603
Joined: Tue Mar 10, 2015 6:49 pm
Location: Eastern Kentucky

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.

THIS^^^^^^^

outbdnut2
Posts: 1048
Joined: Wed Apr 27, 2016 2:46 pm

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.
Dave


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