Is there anyway to add power to a T9.9LPB?

[brancky3]

I've read on older 9.9HP engines it was possible to swap the carb with the F15 equivalent; however, it doesn't seem like there's a 15hp version "sister model" to the T9.9LPB (at least that is obvious). Has anybody had experience with this engine / getting a little bit more juice out of it?

[jerseyjimk]

There’s not much you can do , it is what it is, 9.9 You can try a different prop.

[brancky3]

There’s not much you can do , it is what it is, 9.9 You can try a different prop.

Yeaaaa I know it's already a very small engine, just hoping there was *something* that can be done to it to get a little more speed. I haven't done much research into what a different prop would do - but I have my doubts that much speed could be gained from that alone on this engine.

[jerseyjimk]

Buy a 15 and put 9.9 stickers, I did that to my restricted lake boat, still sucked, but I got from point A to point B

[zenoahphobic]

I have a F9.9 as a kicker motor for a 6.5 meter boat. For that to get the most speed was to use a very low pitch, wide blade prop - they come setup for this called high thrust.
The thing is to make sure it revs to full max(5000?) and that it does not slip too much (just rev like a washing machine not going forward very much).
I found in Australia props for these motors are expensive.

[99yam40]

I have a F9.9 as a kicker motor for a 6.5 meter boat. For that to get the most speed was to use a very low pitch, wide blade prop - they come setup for this called high thrust.
The thing is to make sure it revs to full max(5000?) and that it does not slip too much (just rev like a washing machine not going forward very much).
I found in Australia props for these motors are expensive.

I would think a 4 stroke should rev higher than 5K, but I am not sure on that .

not sure how a washing machine should rev or move forward

[zenoahphobic]

I would think a 4 stroke should rev higher than 5K, but I am not sure on that .

not sure how a washing machine should rev or move forward

Maybe I could have expressed my point clearer. I was referring to the swirling appearance of the water that occurs when an engine tries to push too heavy a boat; where water pushed by the prop finds its way back again. Yamaha specify 5000 - 6000 max rpm presumably this greater range reflects no great gain to rev to 6 thousand.

[99yam40]

a motor running WOT and only getting to the lower end of the range is over propped.
you can run it there, but will not be the best performance
the motor will be happier when propped to reach the top end of the range.
the T motors have a different gearing in lower unit than a regular motor.
meant to turn larger props