bobcohorst
New member
"I have a Sea Ray 300 flybridg
"I have a Sea Ray 300 flybridge with twin MIE 260 engines, factory without modifications, ~800 total hours with Thunderbolt IV ignition. The port engine just won't make power and tach up but the starboard runs beautifully as always. I have had a cruiser for over 20 years and I do my own work unless it is extreme or I don't want to buy the tools. I have checked the fuel system for water / comtaminants-it's clean. I have changed both filters. I replaced the fuel pump (factory original) but the engine it still didn't develop power, smelled very rich and used a lot fuel. I had the carburetor rebuilt by a very reputable local shop and replaced it. the engine runs better but still max 2900 rpm with the starboard engine helping at ~3100 rpm. I ran it for about an hour but the port engine is not developing full power. I also have trouble with it dying at idle (a real piss-off when docking in the wind) after I set the idle at factory spec. The engine starts easily and runs well except for the idle and power problems. I am thinking timing (ignition module puked) or air leak on the suction side of the fuel pump, although the tanks are aluminum and in new condition with clean internals. My next move is to check the timing and perform the fuel system test under load. Any help from seasoned mercruiser guru's would be appreciated. As you know, there's a lot of bogus info out there."
"I have a Sea Ray 300 flybridge with twin MIE 260 engines, factory without modifications, ~800 total hours with Thunderbolt IV ignition. The port engine just won't make power and tach up but the starboard runs beautifully as always. I have had a cruiser for over 20 years and I do my own work unless it is extreme or I don't want to buy the tools. I have checked the fuel system for water / comtaminants-it's clean. I have changed both filters. I replaced the fuel pump (factory original) but the engine it still didn't develop power, smelled very rich and used a lot fuel. I had the carburetor rebuilt by a very reputable local shop and replaced it. the engine runs better but still max 2900 rpm with the starboard engine helping at ~3100 rpm. I ran it for about an hour but the port engine is not developing full power. I also have trouble with it dying at idle (a real piss-off when docking in the wind) after I set the idle at factory spec. The engine starts easily and runs well except for the idle and power problems. I am thinking timing (ignition module puked) or air leak on the suction side of the fuel pump, although the tanks are aluminum and in new condition with clean internals. My next move is to check the timing and perform the fuel system test under load. Any help from seasoned mercruiser guru's would be appreciated. As you know, there's a lot of bogus info out there."