7 Pedal 225 Powerhead on an 88 XR4 Midsection

[VLP]

I have an 88 150 XR4 on the back of my Checkmate. Recent lower unit problems resulted in a brand new Mercury 1.87 ratio lower unit being installed. I have screwed around with that XR4 powerhead for long enough, it runs well, good compression, but is constantly temperamental and I am just sick of dealing with it. I have an early 80's 7 pedal 2.4 liter 225 powerhead that I would like to swap onto my midsection. They are both 2.4's from the 80's, I have already upgraded (durability wise) the lower unit, What else will be needed when swapping these power heads? Will the adapter mount up correctly? water routing the same? and will the exhaust from the XR4 work for the 225 or will I need something different there? I have no problem modifying the exhaust tuner if need be. I have done a lot of searching, but keep turning up different results for things that are close, but not exactly my situation. Any insight would be excellent. And if anyone is looking for an XR4 powerhead or lower unit that needs the forward gear repaired or replaced let me know! :cheers:
Thank you!

[outasite]

You should pull your tuner and cut it to around 6 1/2 inches.or better get an old 200 bell tuner.Yours may be old enough that the tuner is part of the bottom plate.if that's the case just cut it,one side will be shorter than the other!

[VLP]

Okay great, so as far as mounting up, everything should bolt up without modification then? I looked up in the mid and they are definitely two different lengths. I will likely cut them to 6.5" then and look around for an older 200 tuner in the mean time. When you say bell tuner, am I looking for an aftermarket tuner of the time or an older bell style factory 200 tuner? I'm a little bit out of my element with all of this, learning as I go along from the scream and fly crowd! I plan to install solid mounts when I swap the powerhead. Should any gaskets be replaced while I'm in there or can they be reused?

[transomstand]

Bigger gas tank

[VLP]

Yeah, I realize I will be giving up quite a bit of efficiency. Other than that though, all the same?

[transomstand]

Unquestionably change all gaskets. Other than that you'll have few problems, probably just a few odds and ends to change.

[tlwjkw]

if ya change tha mounts check tha pockets for wear... old stuff may look jus fine but thats a place ya don't wanna revisit if it can be avoided... make sure ta get both pieces really clean with new gaskets and hardware (bolts nuts and washers).. better ta do it once... tuner your choice since ya there but you'll never notice tha difference...... lite weight hot rod/stem winder motor, maybe but checkmate, no... jmo.