mercury 2 stroke

[fliar]

Im new to this forum and I hope this is not a duplicate post. "However my question is are a 96 efi 250 and a 99 225 optimax direct exchange power heads. the reason I ask is I have 250 efis and a friend gave me a 225 optimax. Mine are 25 inch shafts and his are 30 inch shafts. So Im trying to decide the best course of action. To put his optimax topend on my mounted 250 mid sections or to mount the optimax and reduce its shaft length to 25 inch. Any help greatly appreciated.

[sosmerc]

Sorry, I don't have a quick answer, but I think I know how you can figure it out. Enter the serial numbers on Mercury's Parts Express website and look up the powerhead base gasket part numbers. If the base gaskets are the same, then you should be able to swap the powerheads from one driveshaft housing to the other without problems. A quick glance at the driveshaft splines will confirm that they have the same spline pattern...I think they do, but that is certainly something you also need to check.

[Capt.Insane-o]

No, the 250's are 3.0's and a totally different animal to the 225 promax. No dice there.

[The Big Al]

Vertical extensions or a jack plate.????

[props4u2]

His question was about a 225 Optimax, not promax. I believe you can switch them, you will have to use the ehaust adapter plate from the opti also, but I believe the driveshaft housings are the same.


Lee

[pyro]

225 opti is a 3.0 motor, is it not?

[Capt.Insane-o]

His question was about a 225 Optimax, not promax. I believe you can switch them, you will have to use the ehaust adapter plate from the opti also, but I believe the driveshaft housings are the same.


Lee


Arrrgh I need to get more sleep. I could have sworn it said pro max..At any rate, if i remember right, and I probably don't, there is some minor water passage differences in the adapter plates. But being you have all the parts on hand anyway it would'nt be a problem. So there.

[chris_lacey]

Be careful of the crankshaft splines.
Early 3.0l (like your 250's) have 8 spline cranks and later have 13 spline. You would need need matching drive shafts (or intermediate shafts).
I'm having an awful time trying to find a used 8 spline 25" intermediate drive shaft for my '95 225.

[fliar]

I have decided to shorten the optimax 225 30" to a 25" . My question is to change the shift linkage and water tube is it necessary to remove the powerhead?
thanks

[Richard]

Yes. Just converted a 30 inch 250 to a 25. Had to cut the water tube and replace the shift shaft. You have to remove the powerhead. I cut the water tube in the exhaust housing with a dremel tool.