Hey everyone....I have a baja 33 Outlaw. Last spring I put on Eddie Marine exhausts on both motors, because the port engine right side stock manifold leaked and nuked the #5 exhaust valve. I knew something was wrong, the
port engine would lag behind the other from 3000 up....and wouldn't rev over 4000 or so. Rebuilt both heads on port engine......ran awesome all summer...then last weekend, we were out all day and ran great then rested in the water with friends and Port engine is starting to lag behind the same way on the way back. Pisser!! I had the marina mechanic take a look.....he said just a little water was on the plug, maybe a bad head gasket or cracked head. No overheating, no codes (I have a scan tool). Maybe the new exhaust manifold is leaking?? Or, maybe the intake gasket leaking water? He said the compresssion was up 4 pounds over the others, because of the water. I'm going down to the Lake of the Ozarks to bring it home (St Louis). I will call Eddie Marine and ask them what they think. Any thoughts from the offshoreonly croud?? Let me know!!

It could be many things. Clear water from cylinder and leak test. That should help point you. How many hours on them total? Have they ever been hot?
Jim

intake

pressure check the coolant system

my first guess would be intake gasket.