9.9? 15?

[stinkbait85]

Have one question. What in the world is the difference in the 9.9 and 15? I can't find one every part# on both are the same. Internal engine part#'s included. I can't figure it out. Please advise

 

[CATransplant]

Re: 9.9? 15?

It depends on the year. On some of the earlier ones, the only difference was the carburetor. As time went by, though, other things were different as well, including the exhaust housing and other components.

So, tell us what model you have and we can tell you what's different.

 

[mikesea]

Re: 9.9? 15?

depends on the years,but,first,the carbs are different,the 15 has larger throat,the exhust also has changes,

 

[stinkbait85]

Re: 9.9? 15?

Ok so here's what I have going on. I have an 82 model 9.9 seahorse tiller steer. Been having problems with it. I came across a 78 15 tiller minus a lower unit for 40 bucks!!! So I bought it. It had points ignition and the 9.9 has electronic ignition. My plan is to put 15 power head on 9.9 pan. I swapped all electronic ignition parts from 9.9 to 15 and holy crap it runs!!!! So what are the differences in carb throat by a measurement standpoint and will the exhaust interchange?

 

[CATransplant]

Re: 9.9? 15?

Ok so here's what I have going on. I have an 82 model 9.9 seahorse tiller steer. Been having problems with it. I came across a 78 15 tiller minus a lower unit for 40 bucks!!! So I bought it. It had points ignition and the 9.9 has electronic ignition. My plan is to put 15 power head on 9.9 pan. I swapped all electronic ignition parts from 9.9 to 15 and holy crap it runs!!!! So what are the differences in carb throat by a measurement standpoint and will the exhaust interchange?

OK, you're past the years when all that was different was the carb. Will the exhaust from the 15 fit in your 9.9 midsection? I have no idea. Will the lower unit from your 9.9 fit on the 15? Perhaps. If that's the case, that's your simplest solution. Then, you have the 15 powerhead on the 15 midsection, with the 9.9 lower unit. If the lower unit fits, you're set. Plus, you get the electronic ignition on the 15.

Swapping the exhaust is a bit job. Swapping lower units is a no brainer, if it'll work. Look at it and see what you think, and if you think it'll work, try making the swap.

You can look at both of the exploded views online and see more info.

 

[bktheking]

Re: 9.9? 15?

Exhaust during those years was the same, difference was the carb and the reeds, they put spacers on the reed plate to allow more fuel flow for the 15. Other than that, lower unit, powerhead etc etc etc is all the same.

 

[oldcat]

Re: 9.9? 15?

Here are some photos of a few of the differences......

The earlier model 9.9 used an even smaller venturi, around .625 I think.

Later (post 85?) 15 megaphone on the left with the early 15/9.9 exhaust tube on the right.

On the powerhead.

Dry stacking keeps the megaphone and exhaust gases hotter for better breathing.

A small amount of water is bled into the mid to help keep things from getting too hot.

 

[AlTn]

Re: 9.9? 15?

Thanks, Old Cat.....good post....great pics!