hello gentlemen, 1987 merc 5.7 260 not reaching wot with a simple 4 blade 16 pitch aluminium prop, i only got 4100 wot rpm with little gas in the tank and me alone on the boat. yesterday i went back to trouble shoot and notice when i hit the throttle, gas is only spraying from one of the nosel on the carb the other one barely spray, so maybe the carb is part of my probleb, last problem from day one the engine vibrate when in nutral and i rev it up, i took of the drive and run it with my garden hose and it still vibrate when i give it gas, kind sound rough, the engine idel fine no miss not shaking. i pull all plug wires while the engine is runing one at a time they all make a difrent so i think all the cilinders are firing, i hope.
as you see i have more than one problem here, gas/vibration your thought guys, after searching this forum i came up with a simular problem a guy was havin where don s work on his boat and found one cilinder was not firing after readjust the valve he got compression in that cilinder, leading me to think maybe i did not adjust my valves right. what i did was loose them one at a time antil it start ratle, i then tighten back just as it gets quiet i gave them another half turn tight.
your thought guys. thanks
as you see i have more than one problem here, gas/vibration your thought guys, after searching this forum i came up with a simular problem a guy was havin where don s work on his boat and found one cilinder was not firing after readjust the valve he got compression in that cilinder, leading me to think maybe i did not adjust my valves right. what i did was loose them one at a time antil it start ratle, i then tighten back just as it gets quiet i gave them another half turn tight.
your thought guys. thanks