Where do I begin?

I am new to this forum and happy to have found it. I am also new to owning an I/O engine. I have a 94 Bayliner with a v-6 Mercruiser. My wife and I took the boat out for the first time yesterday. We were fishing and trolled on the lake using the v-6 for approx. 3 hours. I decided we should stop fishing and "exercise" the motor for awhile. As I began to accelerate, the engine began to cough and sputter and belched out some black dry powder (carbon I assume out of the exhaust) on the surface of the water. It proceeded to get worse and then finally the engine died. I re-started the engine which coughed and missed and sputtered for a while and then finally died again. It would not re-start after that. I believe I may have idled the engine too long and loaded things up with carbon? I am looking for some advice as to where to begin repairs. I realize this may have been a moronic mistake to idle the big engine as long as we did and I hope the repair will not be difficult. Any ideas where I should begin would be helpful.

Welcome to the Forum. A engine serial number would be helpful too.
Yes, you could have fouled the plugs. remove them to see if black with carbon, clean them or replace them.. then check the carb(i`m assuming) to see that the choke plate is operating properly.If you have a fuel/water sep ,remove it and pour the contents into a clear glass jar to inspect for any water.

Bt Doctur, Thanks for taking the time to reply. I appreciate it a lot. I checked the fuel in the filter and checked the fuel pump. Fuel was clean and pump in working order. I checked the coil wire and found that it had been jury rigged. Replaced coil wire and it still didn't start. I then pulled a spark plug and saw that it was seriously goobed up. I purchased 6 fresh plugs and installed them and it fired right up. It wasn't a bad job to get at the plugs and it took longer to go to the parts store and buy them than it did to install them. Pretty easy fix as things go. Thanks again. I hope that I will be able to troll the engine down without having to replace the plugs every time.

roadkingclassic56 said:

Bt Doctur, Thanks for taking the time to reply. I appreciate it a lot. I checked the fuel in the filter and checked the fuel pump. Fuel was clean and pump in working order. I checked the coil wire and found that it had been jury rigged. Replaced coil wire and it still didn't start. I then pulled a spark plug and saw that it was seriously goobed up. I purchased 6 fresh plugs and installed them and it fired right up. It wasn't a bad job to get at the plugs and it took longer to go to the parts store and buy them than it did to install them. Pretty easy fix as things go. Thanks again. I hope that I will be able to troll the engine down without having to replace the plugs every time.

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Ayuh,..... If it continues to foul the plugs, ya probably have a Carb problem, or possibly a bad diaphragm in the fuel pump,....