Difference between 225 and 250 EFI Mercs

[Freedom92]

What makes a Merc 250 any different than a Merc 225? Can I just put a 250 ECM on my 225. Or what to do for a reliable and economical performance booster.

[vnemous]

If your talking 3 liter its computer and 4 hole intake

[davemvegas]

About 25 hp.

[bsumner]

What makes a Merc 250 any different than a Merc 225? Can I just put a 250 ECM on my 225. Or what to do for a reliable and economical performance booster.

4 butterfly intake, 300PM heads, 300 ignition box, 250XB fuel box, fiber reeds, lightweight flywheel, cowl mod.

[Freedom92]

4 butterfly intake, 300PM heads, 300 ignition box, 250XB fuel box, fiber reeds, lightweight flywheel, cowl mod.

I know this isnt what separates the two, but in the interest of more performance, what kind of hp will this configuration yield?

[Freedom92]

About 25 hp.
I knew that was coming

[Todd D]

What makes a Merc 250 any different than a Merc 225? Can I just put a 250 ECM on my 225. Or what to do for a reliable and economical performance booster.

what year is your motor?

[Freedom92]

what year is your motor?

Its a 2002

[TraceF3]

Its a 2002

I've read that the EFI 225 (mine's a 2003) makes closer to 242 HP

[Todd D]

Its a 2002

Then you have a newer motor with a Motorola ecu which is like a 300x not a 300 pro max. You are looking for 300x heads, light flywheel for max go. but to answer you original question the difference between your 225 and 250 are porting in the cylinder sleeves and ecu.

If you want to boost HP I sell billet heads and light flywheels.
www.MadEFI.com

[LongShot]

Todd D knows what he is talking about. His stuff is smooth too....:cheers:

[speedthriller]

Definitely listen to Todd d the guy is a genius and probably has forgotten more stuff than we will ever learn. He LITERALLY walked me through an entire Mercury 250efi rebuild over the phone. I had him on speaker phone as I was assembling everything lol. I must have called him 100 times and he was always happy to help and share his knowledge. He's one of the best people I have dealt with in the marine industry. To be honest with you he's the best person in the marine industry I have dealt with. The parts On his site are top notch.

[Freedom92]

Then you have a newer motor with a Motorola ecu which is like a 300x not a 300 pro max. You are looking for 300x heads, light flywheel for max go. but to answer you original question the difference between your 225 and 250 are porting in the cylinder sleeves and ecu.

If you want to boost HP I sell billet heads and light flywheels.
www.MadEFI.com

So a set of 300X heads and a light weight flywheel is all thats needed? No ecu tune or 300x tuner? What will this give me comparitively?...say 270-300?

[Todd D]

those are just the easy bolt on mods.

port timing is different in the sleeves
the ecu tune 225 to 250 is doable but to jump to the 300x tune it requires different injectors.
the x runs a different reed plate that moves the injectors to the outside of the intake.

[Todd D]

you could cut your tuner.

a strong 250 with higher compression heads should make over 270. It is definitely possibly to get over 300 and possibly 330 ish

[Todd D]

carbon fiber reeds!!

[Freedom92]

you could cut your tuner.

a strong 250 with higher compression heads should make over 270. It is definitely possibly to get over 300 and possibly 330 ish
I have a 225 and cutting the tuner isnt really an option as it is a bass boat and I really dont want the additional noise. Is the 225 efi ecu different than the 250 efi? Im cool with a 25-50 additional ponies. I dont have to have 300 or 335...at least not yet

[Todd D]

Flywheel, ecu, heads and reeds

[Freedom92]

Flywheel, ecu, heads and reeds
Aftermarket ecu or stock one re-mapped