150 and 200 OX66 differences

[younggun]

So I have an 02 OX66 150 on my bay boat and was wondering what the difference in it and a 200 were. I've been comparing part numbers and going through manuals and all I can find are different part number for the CDI box and the cylinder heads. Also the 150 runs a BR7 plug and the 200 runs a BR8. I know the BR8 is a cooler plug that usually means there's more compression there but from what I've seen the 125-130psi across the board on my 150 is right in line with most 200s. What are the actual differences in these motors? If it's simple plug and play and I could find the parts, 50 extra HP sounds nice. Thanks in advance for any help!

 

[tommarvin]

I don't have a clue.
The pistons better be bigger,
Why do you want 50 extra HP.?
Your not one of these guys that fishes till the last second and then turns 5400 RPM 15 miles or longer,back to the ramp this has to be stressing your motor.You don't need 50 extra HP back to the ramp., put the rods down earlier.sir fisherman.
I love you man.

 

[younggun]

Pistons are not bigger. They're the same. And I would like 50 extra HP for several reasons. 1. The boat is rated for 200 and 2. I would like the power if I'm trying to outrun a storm

 

[boscoe99]

You can go to Yamaha's website and open up the parts catalog. Open up the one for your specific model and then open the one for the 200 HP model that is closest to your model.

Determine the parts that are different from your model and the 200 HP model. For the parts that are different, remove those that are on your model and install those that are used on the 200 HP mode.

Looks to be a new short block, cylinder heads, spark plugs and CDI. About $13K if you can find them new.

Voila. You now have a 200 HP engine.

 

[younggun]

I looked through parts catalogs and found all those to be different except the short block so I missed that one. Guess the porting on the motors is slightly different then

 

[tommarvin]

Sounds like your not going to be happy until you have a 200 hp,
Better get a 200HP, and sell your 150hp.
You could add it to your Christmas list.
Merry Christmas man.