HELP!mercury 1992 black max run fine out water but dies in water

[jeremy.lail]

I ran the boat last week and it was then i stopped to fish and the boat did not want to start so i changed the spark plugs and went fishing again i ran the boat about 20 minutes stopped and then the boat wouldnt start again and it was only running at 1100 rpm i took the boat out the water cleaned the carbs and they were fine the boat runs normal out the water but right when i put it back in the water its the same story it wont run over 1500 rpm i pulled the plugs again and their jet black im stumped and worried theres damage inside the motor i need help please any suggestions.

 

[CharlieB]

Re: HELP!mercury 1992 black max run fine out water but dies in water

Test spark, you should have a bright blue sharp crack on each cyl, orange won't do to carry the load once running.

Test stator voltageo on the high speed windings following the direction in the free Troubleshooting Guide from CDI Electronics found using the link at Rapair.com