2700se no power to ignition

[davlloyd]

Hi all,

I have had a recurring issue which has power loss to the ignition. As such no power to the dashboard and of course, engine can not crank. The circuit breaker on the engine has not tripped and I have checked all fuses but all seem good.
I have had this happen before and then it comes good after leaving it for a while. Seems to happen after an extended period running at low or idle revs (Mercruiser 350 Mag MPI).

Interesting thing this time is other electrical components are also not working (2 way radio, front nav lights) which also makes me suspect a fuse blown somewhere. I have looked for the main engine fuse and an ignition fuse but not seeing anything specific to either. The other fuse box on the motor has all fuses as good. I thought there was meant to be a 60 amp ceramic on the starter motor but can not see it. That could be my eyes more then it not being present.

Any ideas are welcome before I give up and pass it to the professionals 😀

[mmwjr]

Check the engine harness to helm harness connector as it may be loose or corroded.

[jrsick]

Since problem is intermittent, wiring harness or a shorted wire are likely sources.
You asked about fuses, you likely have an inline fuse on the red/purple wire that runs from your engine breaker to the ignition switch. If you have one, it will be located between the engine breaker and wiring harness.
Ignition switch could be faulty. Look at the Positive Current Flow checks on page 4A-4 of the 5.0/5.7 manual (not sure of your engine size).
Do you have a power-probe type of tester? It makes this kind of troubleshooting easier because it connects directly to the battery and has long lead wires.

[davlloyd]

Thanks for the replies. I will check wiring harness connections today. I did disconnect all the ones feeding into the engine directly but will check further today. Also checked the ignition to see if anything get through to it and there is no power to the switch so issue must be down stream. Strange that the nav lights, 2 way radio and horn are all impacted but everything else works.

[mmwjr]

Some have experienced intermittent issues with fuse box from corrosion.