Merc 2.5 - difference in 150 hp and 200 hp ??

[CircleHook]

I have three 2.5s - 1@ XR6- 1995, 2 saltwaters @2001/2- I was looking at upping to a 200hp 2.5 but looks
like same block-pistons- exhaust only real difference I can find is WMV-16 vs WMV-18 on the carbs- is that all there is to it?? I could use the extra HP

[mastertrax]

Different carbs (possibly intake too), reeds, intake and exhaust port timing, tuner....I might be forgetting some things. Easier and cheaper to swap powerheads. Sell the 150 or keep it for backup

[wired247]

Carbs and port timing on the cylinders. Little bit higher ports on the 200. Tuner different but that can be cut. Thats really about it. The 150 has idle relief notches cut in the sleeves for a smoother idle. The blocks only look the same from the outside. The porting is the biggest difference. Pistons are the same. Same 5 petal reeds.

[CircleHook]

thanks-

[CircleHook]

Would I lose anything putting merc 200 hp 2.5 powerhead on 150 hp 2.5 mid section ?

[Go Time]

I think the only difference in the 150 and 200 2.5 mids is the length of the tuner....the 150 tuner is several inches longer....not sure the affects of this on performance, but I'm guessing you will have a slight loss of perfromance somewhere in the RPM range.

[s10gto]

Without changing tuner you may have a little less top end. Should have tons of torque.

[CircleHook]

Torque is VERY good- top RPMs not so important- conditions normally to rough for speed anyway- using in the gulf

[malexie]

The 1996 and up 200 blocks are diferent and better.