Differences on Fast Strikes?

[RockinRandy]

I've got a 150 Johnson Fast Strike. It is apparent that the 150 and 175 variants are built on the same powerhead and (I suspect) lower units, just as many 9.9/15hp engines are. The service book is of little help, indicating only that most of the tuning specs are the same. My boat is rated for a 175, so I'd like to find those extra 25 hp.

So, does anyone know what parts differ between the 150 and 175? Is it a matter of changing reeds, shaving heads, larger valves, what? And, would the parts-change to get the advertised 175 be illegal by the no-modifying-motors tournament rules (as in, it must have left the factory as a "175" to be legal, even though the parts would be the same in my 150/175 upgrade as were offered as-stock in the 175)?

[BassNva]

i do believe the carbs are different...not sure what else...i run a suzuki.

[Makitcnt4u]

usually the difference between the two is something in the carb

[catfishtonyd]

You think that's fustrating? I used to have a "standard" Johnson 150. You should try finding out what the difference between THAT and a Fast Strike is. Good luck.
The best answer I ever got was $800.00 and a decale. (There is a bit more, but not a lot. The motor mounts are different for one thing.)

Take your 150 to a good marine speed shop. You can find a lot more than that 25 hp if you're willing to cough up the dough. Speed cost money. Figure about a grand per MPH over what you could get "stock out of the box." How fast do you want to go? (That's an average of course.)

[RockinRandy]

Well, yea fast is better, and I'm all for hi-po mods (everything I drive has been hopped up! ;D). But I don't want to be disqualified from tournaments under that pesky no-hotrod-engines rule, and the boat is only rated for 175.