Recent content by vortmaximum

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    Mercury Fault Code 312 - Port side pre Cat oxygen sensor slow to respone

    I had an opportunity to get out on the water. I took the port side post cat 'D' O2 sensor out and put one of the old ones I had replaced back in. It alarmed again. The smartcraft only says 'System fault' Oxygen sensor not working properly. I reset and turned off boat. A couple hours later when...
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    Mercury Fault Code 312 - Port side pre Cat oxygen sensor slow to respone

    Will let you know exactly what it says next time out.
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    Mercury Fault Code 312 - Port side pre Cat oxygen sensor slow to respone

    Thanks for response. Yes engine cranks for a few seconds then fires. Runs beautifully. Yes post cat O2 sensor, port side. Sensor ‘D’ reading goes to zero or flashes single digits shortly after starting. After I bought the boat in 2015, I had similar issue on starboard, but that cleared up by...
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    Mercury Fault Code 312 - Port side pre Cat oxygen sensor slow to respone

    Same engine. Same issue. Currently my port side post cat O2. Called dealer where I bought the boat used in 2015. Mechanic said bring the boat in. LOL hundreds of miles away. I asked can you just give me some starting points? Bring the boat in. Not possible, went nowhere. I have the techmate, I...
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