Mercury 2.5 150 XRI Performance Changes

[mrichartz]

X2 on James Perry my mid '90s Evinrude Loopers he did the porting, pistons milled to match the finger porting, resleeved all 12(put them in opposite to block the idle reliefs) and machining on my motors and his work is awesome!!.. (actually my motors are 80s,90s mix of parts)

BUT he's right your going to have alot of money into that work if you go that route.. should be able to find a bolt on powerhead

[Dave Strong]

John got 200 with bolt on stuff, no porting.

Dave

[Merc 2.5]

Not afraid its just the max motor size for the Hull is 175

Do not b afraid of putting a 200 on a "175" rated hull. My 18.5 bass boat is rated 175 , I have mild build 200 and the weight is no difference between the 2 , and really ain't hard to drive round 80 , boat wont sit no different n water , only thing would b insurance issues , the 150 xri is great motor , I'm like bullet123 , carb guy ,, but do know they run gud , only thing I worry about on efi is , when is to much compression for the stock ecu or whatever it is ? But compression and a couple bolt ons will help

[gguertin145]

Is there a place online to find those old articles?

I googled and found a few but not the one you are referencing.

[Dave Strong]

Not sure someplace I have the magazines.

Dave

[FORBESAUTO]

The bolt on’s will help. From my experience without porting changes, most noticeable gains will be down low and mid range acceleration. Top end speeds gains are usually smaller. If your looking to be quicker then keep what ya got with bolt on’s. Looking for sizable mph gains either get with someone to port yours or get one of the higher hp blocks.