converting my johnson 9.9 to a 15??

[kpresley84]

I know you can do it i just don't know exactly what to do...? Something with the carb?? i'm looking to this so any help on how would be greatly appreciated!!thanks

 

[Sol Searching]

Re: converting my johnson 9.9 to a 15??

I just did it to my Johnson 6. I got a new 8 horse carb and it took fifteen minutes to change it out. The guy I talked to said it's the same with the 9.9 and 15, same motor, just bigger carb....

 

[kpresley84]

Re: converting my johnson 9.9 to a 15??

so i would just have to get a carb off of a 15 hp johnson?? linkage and everything is the same? thanks

 

[iwombat]

Re: converting my johnson 9.9 to a 15??

Well, no not exactly. Let's start with the year of your 9.9 and go from there.

 

[R.Johnson]

Re: converting my johnson 9.9 to a 15??

Carb. reed stop, exhaust tuner, and when your done you probably won't hardly see a difference. A carb change alone will do nothing.

 

[wbeaton]

Re: converting my johnson 9.9 to a 15??

Completely depends on the year. There were about three years in the 1970's where a carb swap was the only difference. However, the 15 hp was apparently only outputing about 13 hp so the difference wasn't very noticeable. You need to look at the parts catalogs over at the BRP site and see what the difference is between your motor and the 15 hp of the same year.

 

[kpresley84]

Re: converting my johnson 9.9 to a 15??

it is a 1977 Johnson 9.9...so would you say it would be worth the time and effort to do this change or would i be better off just leaving it alone?? it doesnt run great right now so i was thinking of doing this while i had it apart..Thanks..

 

[wbeaton]

Re: converting my johnson 9.9 to a 15??

Personally, I wouldn't bother, but its up to you. If you're just looking for a project and don't mind dumping a little cash then go ahead and try. Your motor may actually fall into the magic period where it really is only a carb swap, but I wouldn't expect much difference. Also, finding a good 15 hp carb maybe harder than it sounds. Either way, you need to check out the parts diagrams at BRP before you start buying parts.

 

[iwombat]

Re: converting my johnson 9.9 to a 15??

You probably ought to talk about why you want more HP at this point. Could be that you'll never see 15hp even with a real 15hp (or 9.9 for that matter). Describe how the 9.9 is performing on your boat.

 

[kpresley84]

Re: converting my johnson 9.9 to a 15??

heck i'm just a typical male!! MORE POWER!! lol. Like i said before i haven't really ever got to see the motor run at full potential b/c it has been messed up since i got it and still trying to diagnose the problem..Just figured it would never hurt to have a lil more HP..i was going to try and do this while i messing with it trying to get it to run right, but if i can't just do a carb swap then i probably won't mess with it.. thanks yall

 

[iwombat]

Re: converting my johnson 9.9 to a 15??

The idea I'm trying to get across is that by spending a little time setting up the 9.9 properly for the boat you'll see far better performance enhancement than putting a 15hp on with the same un-optimized configuration.

 

[kpresley84]

Re: converting my johnson 9.9 to a 15??

what do you mean? i'll always listen to pointers for better performance..

 

[CATransplant]

Re: converting my johnson 9.9 to a 15??

First step is to get the engine running properly. Whatever that takes. You said your 9.9 doesn't run right. Fix that and your problems will mostly be over.

Second step is the boat. How is it loaded? Weight distribution is everything with low horsepower boats. Too much weight in front or back can ruin your chances of getting the boat up on plane.

Third step is trim. Your outboard has several possible trim settings. Finding the right one may make a huge difference. Experiment.

To go further, we need to know about your boat.

 

[mikesea]

Re: converting my johnson 9.9 to a 15??

while your at get a set of boyseen power reeds too.