9.9 to 15 easy conversion?

[pcrussell50]

hi, i have a johnson 9.9, E10RSC. i think it is a 1990. anyway, i _think_ it has the same chassis as the 15hp version of the same year. so i'm wondering if this is one of the ones where a mere swap to the 15hp carburetor will convert it to a 15? i've heard that for some engines, it really is as simple as that, and for others, it's pretty involved. i'm only interested if it's easy. otherwise, it runs great. thanks, all.

-Peter

 

[Vic.S]

Re: 9.9 to 15 easy conversion?

That's not a model number for a 1990 Johnson.
Johnson numbers begin with a J, Evinrudes begin with an E. Not that it affects any thing much other than paint and decals

ES are the year letters for 1990. Your number does not match anything.

I suggest you sort out the year and correctly ID your engine then go to one of the parts lists Shop.Evinrude.com for example and compare part numbers of 9.9 models and 15hp models. Make sure you check the major engine parts like crankcase, head, inlet manifold.

The 15 will have a different prop, I would also check the gears although i expect they are the same.

By doing that you should be able to determine if the conversion is viable or not

 

[freddyray21]

Re: 9.9 to 15 easy conversion?

there are several threads on this. My advice. Buy a 15 hp

 

[npd4432]

Re: 9.9 to 15 easy conversion?

here is a wealth of information on these motors, it looks like you can do it, depending on the year of your motor.

http://www.sschapterpsa.com/ramblings/OMC/OMC info.htm

 

[Dhadley]

Re: 9.9 to 15 easy conversion?

What kind of rpm are you turning the 9.9 now?

 

[pcrussell50]

Re: 9.9 to 15 easy conversion?

Ok, i boned up some info when i started this thread. thanks to all who answered so far. it IS actually and evinrude, not a johnson as i had first claimed. the part number is E10RESC, where the first time, i left out a key letter. sooo, it is:

a 1990 evinrude 9.9

now that we have that estabilshed, i _thought_ some of these motors were a simple carb change away from the higher horsepower version. iow, a simple carb change can take you from a 9.9 to a 15. when i went to the evinrude site and looked at their online parts/diagram pages, it showed the intake manifolds as being identical, and with the same part numbers, from 9.9 to 15. the only difference was the carb. so, if there is nothing more to change besides the carb and prop, i'm interested. if there is more to change than that, i'm not interested. on edit: i just compared the crankcases between the two, and they are identical part numbers, too.

as an added note of interest, when you look at the evinrude parts page for either engine, they BOTH list the same selection of carbs. IOW, when you're looking at the 9.9 carb list, it lists the 15hp carb as one of the choices, and when you are looking at the 15hp page, it lists the 9.9 carb as one of the choices. presumably, the buyer has to pick the right carb for his engine. it would be a shame if someone "accidentally" picked a 15hp carb for his 9.9 and ended up with more power, now wouldn't it?

-Peter

 

[pcrussell50]

Re: 9.9 to 15 easy conversion?

ok...thanks to that link a couple of posts above, it looks like there were a couple of other small differences, too. entirely doable...but i'm far too lazy right now, as i rarely use my 9.9 and it works like new. because it almost IS new. an old lady had bought it for her husband, who died before he got to use it. she kept it in her garage till 2007, when she died, and i bought it for $180 at the estate sale...essentially, brand new. and it runs like brand new, too.

-Peter

 

[Dhadley]

Re: 9.9 to 15 easy conversion?

What rpm does it turn now? The main difference between them is they are rated at different rpm. Yes, the head and carb are different. But. if you're only turning 5000 rpm as a 9.9. putting a bigger carb on won't make any difference. Other than to slow down the holeshot.

 

[pcrussell50]

Re: 9.9 to 15 easy conversion?

What rpm does it turn now? The main difference between them is they are rated at different rpm. Yes, the head and carb are different. But. if you're only turning 5000 rpm as a 9.9. putting a bigger carb on won't make any difference. Other than to slow down the holeshot.

Hmmm, i don't know what rpm it goes to. How do i find out? is there some kind of special tachometer that keys off sound impulses? Oh, and i didn't see a listing on the evinrude parts guide for a head, unless the head was part of the "crankcase, complete". in which case, both are identical part numbers, 9.9 to 15. according to "the link", there's a tuned exhaust for the 15hp, and some kind of thing attatched to the reed that lets it flow more air...or changes it's resonance, or something. and that the 9.9 is rated at 5000rpm, and the 15 is rated at 5500rpm. obviously things like tuned pipes and reeds probably have greater effect on the top end. so it all makes sense, anyway.

-Peter

 

[jspringator]

Re: 9.9 to 15 easy conversion?

http://www.tinytach.com/tinytach/index.php