[plmbr]

Hi all; I have a few more questions about converting a 9.9 to a 15 . I just rebuilt my evinrude 9.9, and I've found a 15 hp carb. I thought my motor was a 1990 when I posed my other questions on whether just using the bigger carb. and found out for a 90 to 92 it would as they have the same exhaust tube round on the bottom end. But since have found out my motor is a 1989 and the exhaust tube is square on the end with a gasket.
My questions are
1 - Will the square tube be sufficient to get rid of the exhaust if I install the 15hp carb.
2 - If not and I have to change to the rounded end tube of the newer model will the outer exhaust housing of my 1889 9.9 be ok, or would I have to get one of the newer models as well.
I'd really appreciate an answer of some kind as I'm anxious to get a new carb on the motor whether it be the 15 or getting another 9.9 carb motor. as the old one is cracked. Thanks ...Plmbr

[digitalkreation]

Did you ever find an answer to your question? I've got a 1986 9.9 and I'm converting to a 15. I've already purchased the carb (got 2 actually) and the inner exhaust tube, but as you have seen, it's shorter and rounded, while the 9.9 is longer, square and seals up tight at the bottom.

I'm wondering if the rounded tube is fine to just go in as it is, and not to worry about it being shorter and not sealing up tight, or if I need a complete exhaust housing to go with this inner tube I've got..

[Whoopbass]

Just change out the carb and run it.
I wouldn't mess with the exhaust tube besides what are you going to get .5 more hp or less with the larger tube?