1992 Evinrude 9.9 2 stroke running rich with early 1987 15hp carb

[racerone]

It is easy to swap parts and turn the actual 15 HP into a long shaft here.---A worthwhile step and fun to do.

 

[DeanHensler]

It is easy to swap parts and turn the actual 15 HP into a long shaft here.

I think the short to long shaft conversion wouldn't be a big deal, but Tiller to remote controlled might be a big pain in the ass.

 

[RaisedByWolves]

It certainly sounds like the next logical step is a good cleaning and inspection of the 15hp carb.
.

That would have been the first logical step with a used carb.

Put a carb kit in it and check the float height.

Then go from there.

 

[Tim Frank]

It certainly sounds like the next logical step is a good cleaning and inspection of the 15hp carb.

Yes....and you do not give the history of your '87 15 HP. If you have had it for awhile and it has run OK....no worries. If not, you need to verify that the carb is correct and not re-jetted from OEM specs.
I am not sure how you can tell the part number for the carb, but you know how to check that jet now,

If you kept that jet from your previous adventure, try it as a quick R&R. Worth a shot.

If anyone else has been down this road I would appreciate any success stories they had.

Is there any chance that the power heads would swap? That would be the simplest solution....unless you really don't want to miss any of the fun.

For everyone else with useless comments like "buy a bigger motor", please understand I'm just having fun tinkering around here. I'm not broke down on the side of the road begging for a tow.

But you are begging for information....
They are only useless comments if they ignore the basic parameters of your original post. IMO your post #20 should have been included in post #1.

 

[flyingscott]

There is nothing you can do to make that 9.9 go faster on that boat. What you don't realize is that the 15 hp is making its power at 6250 rpm. The 9.9 hp makes it power at 5500 pm. Neither of those motors are capable of spinning the prop to there recomended RPM. Your plugs are wet because your motor is loading up. You probably went backwards in power because of the larger venturi size in the 15 hp carb. The 9.9 carb works better in the low to mid range rpms which is where your motor is working. Your boat is way to large for the motor you have. And there is nothing you can do about that no magic fix. If you don't want a bigger motor buy a smaller boat

 

[kbait]

Agree with flyingscott^. If your pushing a barge, the 15 carb’d motor is unable to reach the higher rpm’s where the increased power is seen.. possibly wet plugs as it’s loading up instead of winding up.
You likely have a 9x10 standard prop now. You want much lower pitch (2nd #)..like lower gear in a car for more rpm’s at slower speeds. Look here at prop sizes:
https://www.iboats.com/shop/boat-pr...ke-thru-hub-exhaust-13-tooth-spline/1992.html