82 9.9 Evinrude rejetting to 15hp

[c11343]

Has anyone rejetted a 9.9 to a 15 successfully, i ordered the new jet and it made the engine run as if it is flooded all the time. The jet was numbered according to the factory specs. I am wondering if there is a restrictor in the intake for fresh air or on the exhaust side. The only difference I could find in the factory specs was the main jet is different between the two horsepowers and of course the stickers and serial #'s. Would love to solve this problem and go fishing! Thanks for any input.

 

[FlyBoyMark]

Re: 82 9.9 Evinrude rejetting to 15hp

Re-jetting will ony flood the engine and it will not run properly..Earlier models have bigger carburator and newer models have different induction manifold AND carburator....Rejetting Never makes the engine develop horsepower of next Hp model up..This is an "old wives tale". Your particular model MAY be able to have a bigger 15 HP carb installed(get from outboard bone yard or pay through the nose for a new one)...some of the other guys on this board that are more familiar with OMC products can answer this..

 

[OBJ]

Re: 82 9.9 Evinrude rejetting to 15hp

Hey RV. Flyboy is correct. Just adding jets will not help but only flood the engine. If you look at the throat of the carberator of your 9.9, you can see that at best the throat is only about the size of a nickel. The throat of a 15 carb is about the size of a quarter maybe a little more. Your giving it the gas but the air is not there so to speak. The 15's also had shims between the reeds and reed stops and a "tuned" exhaust tube. If you want 15 you need the whole carb, reed shims and exhaust tube. Hope we've helped.

 

[FlyBoyMark]

Re: 82 9.9 Evinrude rejetting to 15hp

As an added note..You might want to look into Boyesen reed conversion for about the same money instead of using stock reed stuff and in additon to bigger carb....

 

[the machinist]

Re: 82 9.9 Evinrude rejetting to 15hp

The above posts give good info. Here is a website that may help <br /><br /> http://www.pugetsoundanglers.org/Fishing Info/Johnson 9.9_15.htm <br /><br />I have been there & done that, it will just make your engine blubber & have less power than with the smaller 9.9 jet.<br />My thought is you can get by without the exhaust manifold, & just change carbs, as the special 15hp manifold did not show until they changed the hp ratings to match the Japanese motors.

 

[c11343]

Re: 82 9.9 Evinrude rejetting to 15hp

Thanks to all, think I will simply replace the 9.9 jet and buy a doel-fin and settle for what comes up in performance. Then possible a new motor if this doesnt work. Again a sincere thank you.