9.9 Evinrude converted to 15 hp?

Joined
Feb 26, 2003
Messages
8
Wanting to get more from my 1991 Evinrude 9.9, how can I convert to 15hp? Where do I need to get the parts? The 9.9 needs some more umph, dont have the funds to go out and pick up larger motor. What price am I looking at? Thanks.
 

ebbtide176

Commander
Joined
Jan 22, 2002
Messages
2,289
Re: 9.9 Evinrude converted to 15 hp?

hello. you might want to use the 'search' function at top of page to look over the few past discussions of this issue. maybe use "9.9" or "converting 9.9" for matches. i believe i've seen it at least twice in the past year...<br />-just a thought<br /><br />from what i remember, its not as simple as swapping out the carb.
 

digimortal777

Petty Officer 1st Class
Joined
Jun 25, 2002
Messages
214
Re: 9.9 Evinrude converted to 15 hp?

i dont understand why people would want to do this conversion , you arent really going to get a huge jump in accelaeration and speed , just more gas bills<br /><br />you have to take into account the 9.9 and 15 are going to be geared differently , all you will do to your engine is exeed the max ratred rpm and eventually blow up your engine
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: 9.9 Evinrude converted to 15 hp?

Actually the gear ratio is the same. So is the bore and stroke. Yes, there are some differences like heads and carbs but they are minor. Thats why when someone does spend the money they usually are disappointed. <br /><br />I happened to be looking at a 1992 book and the 9.9 is rated at 5500 rpm with a operating range of 5000-6000 rpm. The 15 is rated at 6250 with a range of 5500-7000 rpm. Does this mean that if we put a 9.9 on a dyno and loaded it to 6250 that it would be 15 hp? I bet it would be close. <br /><br />I would work on the set up and if I were going to spend money it would be on a prop. <br /><br />Good luck!
 

Mikedg

Petty Officer 2nd Class
Joined
Sep 3, 2002
Messages
131
Re: 9.9 Evinrude converted to 15 hp?

While all the specs are the same, the cost to convert a 9.9 is higher than selling it and buying a used 15. For motors produced in the 80's and earlier, you could just upgrade the carb to bump the motor to 15hp. From the late 80's on, the motors require changing out of the exhaust manifold, as well as the carb. Way too expensive.<br /><br />This is probably not the news you were looking for, but I researched it in great detail trying to upgrade my '91 9.9.
 
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