Mercury 225 EFI Not same as 250 EFI (3.0L)

[bep078]

I was considering to upgrade my 2006 mariner 225 efi's ecu to the 250 one. My Mariner dealer told me that the engines is not exactly the same. There is a difference in the exhaust ports in the 250 EFI (don't know what and how exactly), and if I install the 250's Ecu on my 225, the engine could go slower due to the fact that the 250 ECU is mapped to worked for these differences in the exhaust ports. The part number for the bare engine block for the 250 EFI is different to that of the 225.

Has anyone ever assembled a modern 225 and 250 EFI to be able to confirm this as an ECU is quite costly and I don't wish to spend those $$ for nothing.

Many thanks.

[flabum1017]

A friend of mine wanted to do the same with his opti's. The porting is different in those as well. Simply put, the porting and tuners work hand in hand with the programming. If you put the 250 computer on a 225, it will want to deliver more fuel to a block and tuner that is not pushing more air. That is as simple as I can put it.

Give Brucato a call and see what they got for ya.

[bep078]

Thanks.

[tunnelmann]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" UNSELECTABLE="on" width="100%"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">I was told that the 225 & 250 3.0 L EFI were the same block But the opti 225 DFI is differnt has differnt port timing I know this because I have a 250 EFI & a 225 opti DFI sitting on my work bench I wanted to put heads,EFI,& electronics from blown 250 on the 225 I picked up with no elec's
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[87sutphen]

I think the 225 and the 250 efi motors are the same but the 225 and the 250 optis or dfi motors are different

[flabum1017]

there are three diff blocks for the mariner 3.0:

885- 9811T92 225hp
885-9811T91 200hp Work
885-9811T93 250hp


The blocks are different, porting is different. It's your money, your call.

[bep078]

Thanks for your reply.

Has anyone ever tried a 250 ECU on a 225?

[tunnelmann]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">Check post by daddio about 225/250 swap
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