75hp vs 90hp

[jigginjim]

I had the same type of differnce between My 60hp to a 70 suzuki. I was told it was RPM, 60hp was to run at 5400rpm, the 70 ws to run at 5900rpm. So I ran it 6300rpm. I like my boat to run the raged edge if possible. MY need for speed.

[196thDLR]

GS: Please, one more question. Is this something I can do, or , should I take to someone who is more mechanical than I?

[Gator Slayer]

I don't know what your mechanical ability is, however I was told it's a simple 15 minute job. Just be careful and don't use excessive force, You're dealing with plastic and metal so you know what will break first.

Troutteaser is correct, this only applies to EFI motors. Sorry if I mislead you.

[196thDLR]

GS: Thanks for your efforts. This is a 2003 motor I am asking about. So apparently, the changes are not very simple.

[solbes]

I will be trying this in the spring on my '08 EFI. Can't wait to hit the water. Many thanks!

[TROUTTEASER]

Still great information. I have a 04 Yam 75 I would have loved to have converted. I'm 1 year off. I've already thought about an upgrade.

[Eyefishalot]

I hear a lot of talk about this but I haven't heard anyone say they've taking the restrictor out and gained mph or tell a big difference. I like to see what the results are.

[walleyewild]

I have a 135 opti and the only difference between the 135 and 150 is the gear ratio in the lower unit.

I could see where they would turn down the HP with airflow restrictor plates, they use them in NASCAR, why not boat motors?

Let us know what you find, it may be nothing more then pulling the restrictor, but it could need to be rechipped as well with efi to get the fuel flow rate up a little higher, to increase the rpm on the motor.

Mine does 45 with my boat, not even thinking about tweeking anything. Maybe a new stainless prop but that would be it on my boat.

WW

[coombia21]

Not to take over the thread but what would I have to do to my 2008 15hp honda to convert it to a 20hp? And a 2004 9.9 to a 20? When I bought the 15 the dealer told me that the 9.9 15 and the 20 all have the same motor and the same block same everything accept for 1 or 2 parts, does anybody know what these two parts are?

Thanks dan

[boatfixer]

I have a 135 opti and the only difference between the 135 and 150 is the gear ratio in the lower unit.

True the ratio is different. the 135 is 2:1 and the 150 is 1.87:1

The 135 does have an air restriction and the PCM is programing is different and will not adjust to the increased air flow.

[delcecchi]

Motors made after some date are unlawful to modify, since it might increase their emissions. And since I am sure the FM readers are all good law abiding citizens the above posts are obviously for educational use only as examples of what could be done. :-)

[boatfixer]

Good point del

[Get'n Jiggy]

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