Re: 9.9 johnson to 15 hp conversion
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Posted by Michael
(126.96.36.199) on September 21, 2005 at 13:57:59:
In Reply to: 9.9 johnson to 15 hp conversion posted by jerry on September 20, 2005 at 12:07:51:
I have done this conversion many times.
The only parts that you need to change are the carb and the exhaust tube. Some very early 9.9/15hp motors had the same reeds, but the 15hp had a spacer under the reed stops to allow them to open more. To change the exhaust tube you will have to pull the powerhead. I have found that there will be a noticable increase in performance with just a carb change.
Make sure you really got a 15hp carb. Look down the throat of the carbs, the 15hp one should be noticably larger. If it is, then there is some other issue with your motor.
What rpm do you get at WOT?