what to do?

what is the differance in a johnson 9.9 and a 15hp?

Re: what to do?

5.1 horsepower (?)

Don't mean to be a smart aleck.

Guess we're confused with your question.

Are you trying to choose between one or the other?

Are you thinking of attempting a conversion?



Bob

Re: what to do?

The top end speed for the 15 was only a few more miles an hour then the 9.9 on my rig but the hole shot and pick up speed is way better on the 15.

Re: what to do?

About 50% more power.
Or was there something more specific you wanted to know ???
Welcome to iboats

Re: what to do?

if you are thinking about trying to increase the 9.9 to a 15. it has not been "proven" that you pick up any horsepower.

Re: what to do?

My Johnson 8hp was a bored out 6hp. The two motors weighed the same.

Re: what to do?

A fishing buddy of mine, who likes to out do averyone else, purchased a 1990's model Johnson 9.9 and asked the outboard mechanic how was the cheapest way to up the horsepower as he wanted to be the fastest boat on a lake that had motor restrictions past a 9.9HP.
The mechanic replyed that a 15 HP's only difference from a 9.9HP was the larger carb.
My buddy purchased a 15 HP carb and put it on the 9.9 and it supposedly ran faster (I never rode in the boat with the smaller carb). I believe he paid around $250.00 for the new carb back then.
Maybe the mechanic knew this guy and took the easy way out of this or maybe this is real, I'd ask an older Johnson outboard mechanic if this was trueor not.
Don