1988 mercury 100hp motor

[Amor]

the bottom two cylinders won't kick in over 1800 rpm. The mechanics say it is an electrical problem, but are stumped as to what. We have replaced the switch box and it worked for 10 minutes and then cut out again. What could the problem be?

 

[12Footer]

Re: 1988 mercury 100hp motor

Check the timing. It may be passing with the spark advance advanced (in the event the timing has been moved). They rarely move by vibration.<br /><br />Check the plug condition compared to the other cylinders, and check the compression. Dump the carb bowls,as it maty be water in the bottom bowl.<br />It will collect there first.