My 93 225 TXRR has been sitting for about 18 months. The engine ran perfect up until the day I thought I would do some preventative maintenance. The head gaskets were swelling and after seeing a friend spent $1,500 on a rebuilt power head (water intrusion = blown piston) I thought I would be ahead of the game. Long story short, due to breaking off the head bolts, then illness in my family the boat has just sat until now. <br /><br />Ive drained all the fuel from the boat, replaced the fuel / water separator and drained the fuel from the fuel filter. Ive replaced the following items: Head gaskets; Head Cover gaskets; Anodes on the block; Inner & Outer exhaust gaskets; Thermostats; Pressure Control Valve; Water Pump; Lower unit gear oil; Fuel Feed assembly (check valve); Plugs; Primer bulb.<br /><br />The engine starts fine, idles @ 700 rpm with the muffs on and will rev up to 5,000 rpms with no load in the driveway. I first ran the engine from a separate tank to ensure I had good fresh gas.. Seemed ok with the spare tank and with the new gas in the boat tank in the driveway with the muffs on. Compression test (no leak test run) when warm 123lbs per cylinder. In the water it runs ruff (not missing) and will not go over 1800 rpms. When I got home I pulled the plugs and they looked fine, although plugs from the lower two cylinders (5 &6?) looked different, almost like they may not be getting as much fuel as they were cleaner that the others. I checked the fuel filter and it was fine too.. Re-ran compression test, still @ 123.. I have not touched the carbs; fuel pumps; or the yamalube oil in the tank.. How do I diagnose this, where should I start? I did not want to just blindly start.. Any guidance you can provide in narrowing this down?
