More HP from a 90 HP Evinrude

G

GB1073

Cadet
Joined
Dec 4, 2010
Messages
6
I have a 1989 90 Evinrude on a 160 Freedom Four Winns boat, the boat is rated for up to a 120 HP OB.
As the bore and stroke is the same for a Evinrude 90, 100 and 110, what is the difference to get the additional HP from the same size moter? Can the difference be retrofiffed to the 90 HP?
Has anyone done this?
Is anyone out there that has more an a 90 HP on a 160 Freedom and can comment on the performance?
Or should I be considering a change of motor?
Thank you.
 
Faztbullet

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,616
Re: More HP from a 90 HP Evinrude

Get a 120 looper and you will see more torque on bottom end and less fuel usage...
 
Bifflefan

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
Re: More HP from a 90 HP Evinrude

The exhaust and possibly the carbs are different.
What "performance" are you looking to improve?
My old 16' with an 85 HP on it when faster that I wanted it to, she would 50MPH with a 21p on it, but dang, where do you need to be that fast in a 16'er.
If you want more motor, the best idea is to buy it rather that try to swap out parts.

Good rule of thumb is, "if you want a faster boat, buy a faster boat".
Get yourself a nice 21'er with a 300HP in it and you go hell-bent until you run out of gas.

Welcome aboard.
 
E

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: More HP from a 90 HP Evinrude

The 89 110 hp engine has larger throated carbs, higher compression heads and the bubble back perormance exhaust. Also Likely the 110 block had the intake/exhaust ports machined higher during manufacture at the factory. Adding the bubble back and porting to a 90 requires complete engine disassembly. The carbs and heads are bolt on changes. If you purchased a similar 110, I'm not sure you would see much difference in the hole shot between the two engines. The 110 will outrun the 90 at top end.
 
G

GB1073

Cadet
Joined
Dec 4, 2010
Messages
6
Re: More HP from a 90 HP Evinrude

Thank you all for your suggestions.
What is a looper motor?
 
E

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: More HP from a 90 HP Evinrude

Looper or crossflow engines refers to the fuel/air scavenging method that goes on in the combustion cylinders. The older technology crossflow engines all have domed pistons with solid skirts to direct airflow within the cylinders. The loopers engines have flat topped pistons with vented skirts, different porting so that the fuel/air mixture flows in a "loop" in the combustion chambers. Loopers are generally more fuel efficient.
 
You must log in or register to reply here.
Top