XXL to XL conversion questions

[Robalo1226]

Hi Mercury owner/mechanics.
I just bought a clean 2003 optimax 225 XXL. Since I need a 25” on my boat we took off the 30” space and he gave me a 25” lower. He said it’s an easy fix to swap out the need parts but I’m second guessing that now. Please let me know if I’m correct;


1. Swap out the shift shaft in the upper.
2. Swap out or maybe cut the water tube.
3. Cut and rethread 4 shafts or buy 4 new shafts pull them out and replace them (I think I’d rather replace).
4. Maybe something with the exhaust?


Do I have to remove the powerhead to replace the shift shaft and/or the water tube?
Is this a big job? Seem people always offer a 25” when selling a 30 but maybe it’s a bigger job then I expected. Hoping to hear there’s a way around taking off the powerhead.


Thank you!

[Robalo1226]

Serial number OT775102

[EuropeanAM]

You will need to remove the Powerhead AND the Adapter Plate to change the water tube (and the shift shaft).

Replace the studs in the driveshaft housing with the correct length studs (normally 8M0008031, 4 Required).

[Robalo1226]

Thank you, any thoughts on the correct cost or maybe amount of labor hours for a mechanic to do it?

[Robalo1226]

Thank you EuropeanAM I actually bought the incorrect studs. I ended up buying 8M0070951
just checked and you’re right. I should have 31s
thanks.