9.9 HP upgrade to 15???

[Hunt2871]

Ive been told that for about $150 a 9.9 HP Yamaha can be upgraded to a 15 HP. Is this true? Is it possible to upgrade a 4 stroke as well as a 2 stroke? Will the upgrade harm the engine?

 

[JB]

Re: 9.9 HP upgrade to 15???

Give the knowitall that told you that $150 and see what he does.

 

[mjbrueck]

Re: 9.9 HP upgrade to 15???

On my 2002 Mercury 4-stroke (Yamaha powerhead) it's true, although a Mercury carb is closer to $200. I believe the carburetor is also made by Yamaha (metric bolts), but I'm not sure. If it is the same, the carburetor float bowl assembly is different, so you can't just replace the jets.<br /><br />On my boat, it went from a top end of about 16 mph @ 5100 rpms to 20 mph @ 5500 rpms. With two people, I can still reach 20 mph, whereas, with the 9.9 carb it would only reach 11 mph. <br /><br />I don't know if the same is true for 2-strokes.

 

[TOHATSU GURU]

Re: 9.9 HP upgrade to 15???

That 2002 Mercury is a Tohatsu...All the way through.

 

[mjbrueck]

Re: 9.9 HP upgrade to 15???

That 2002 Mercury is a Tohatsu...All the way through.

That's what I thought too when I got it, but you were the one that told me it wasn't. After looking into it, I found out the block is the same size as the Yamaha's.

 

[JB]

Re: 9.9 HP upgrade to 15???

Perhaps the Yammy is also Tohatsu made.

 

[rodbolt]

Re: 9.9 HP upgrade to 15???

about now a model number would be useful