Mercury 150 EFI 2006 #1B424789

by Jeff Fortezzo
(Montgomery, Tx)

Took my boat in for annual engine maintenance (it was running great) and my mechanic changed the water pump impeller, fuel filter and serviced the lower unit. First time I took it out after servicing, while cruising at 4000RPM, I noticed a slight un commanded power reduction and then a single beep (very similar to when the ignition key is first turned). I reduced power to min forward speed and was able to slowly motor to my fishing spot. After fishing for about 30 minutes, tried to get on plane to return to my marina and the same thing happened again--un commanded power reduction and then a single beep. I tried one more time, but couldn't get on plane, so slowly motored back home at min forward speed. Mechanic checked over boat ran it several times and couldn't duplicate the problem at his shop. I launched the boat and motor started once, then wouldn't start again. Mechanic came and couldn't start it either, then noticed a blown coil fuse. He took it back to shop, and replaced the ignition switch and main power relay. I launched the boat again and it got on plane for about 5 minutes, then the un commanded power reduction and single beep. Called my mechanic and he wouldn't return my call.

Found a new mechanic, he

hooked up the computer, and sees there was an overheat/overspeed during that first engine run after annual maintenance. He also found a damaged coil, and an improperly installed impeller and impeller housing. He launched the boat and said it ran ok although it idled rough. I took boat out for a short spin and it ran ok although the engine really was running rough in idle. Took boat out again and had several instances where there was an un commanded power reduction and single beep. Took boat back to new mechanic and he says there was a service directive (or something like that) which stated there was a problem with the coils and recommended that all coils should be replaced. I had mechanic replace all the coils, he checked and replaced 4 of the plugs and the motor is still giving intermittent un commanded power reduction and a single beep.

Mechanic showed me the computer shows no new faults. He checked, cleaned and reattached several leads on the motor and the battery. He loaned me a different wiring harness and ignition switch and I tested the motor with the new harness and switch--motor runs better but still get the intermittent power reduction and single beep. Pulling my hair out, this is prime time for fishing in Texas. Any ideas what is wrong?????