Engine performance 60hp vs 75hp

[guy74]

I have a chance to upgrade the 1988 60hp Johnson currently on my boat with a 1982 75hp Evinrude. What kind of performance gains should I expect with thas change. Both have very good compression (135-140) and run very good. Currently I get 33-35mph @ 5900rpms out of the 60hp with a 13.75 X 15 prop. I'm looking for just a little more power for not much $. Any advice would be helpful.

Thanks,
Brian

 

[Chinewalker]

Re: Engine performance 60hp vs 75hp

Hi Brian,
Realistically, you're not going to see much of an increase. Your 60hp is the later "big block" version at 56-cubes, while the older 75 is the "small block" version at 49 cubic inches. The 60hp was also rated after they went from powerhead rated to propshaft rated horsepower, so your 75 is probably closer to the mid 60s in propshaft terms. Bottom line, I don't think it would be much of an upgrade.
- Scott

 

[guy74]

Re: Engine performance 60hp vs 75hp

Hi Scott,
Thanks for the reply. I was wondering about that, I knew that they changed to rating at the prop beween the 1982 and 1988 model years. So I guess I won't waste my time with that change. I guess I'll wait til I find an 85 or 90hp for an upgrade on my boat.
Thanks,
Brian

 

[Chinewalker]

Re: Engine performance 60hp vs 75hp

Hi Brian,
If you go to the V4 you will see a BIG increase in low end kick and a decent increase in top end. You'll also see a pretty big increase in fuel consumption, although the V4s aren't too bad if you're not on the throttle too much...
- Scott

 

[guy74]

Re: Engine performance 60hp vs 75hp

My cousin has a GX 150 Gastron with a 90hp Evinrude. We use each others boats and go boating together all the time. It definatly uses more gallons per hour at WOT, but when we cruise together at around 30 mph it seems to use about the same amount of fuel as my 60hp. I guess it doesn't have to work as hard to go the same speed. Anyway it gives his boat the kind of perfomance I'd like to get out of mine. We originally bought the GX 150 to get the motor for mine, but decided it was too good to part out. So now I'm looking for a good 85 or 90hp motor for mine. I just haven't found one cheap enough or close enough yet. Then I found a bargin on this 75hp evinrude and was wondering if it would be good enough, but I guess it wouldn't be worth the trouble.
Thanks again for your time and expertise.
Brian

 

[Chinewalker]

Re: Engine performance 60hp vs 75hp

If the 75hp is a bargain, get it, tune it up with new waterpump, etc. and resell it. Use the proceeds to find your 90...
- Scott