Help - Optimax in guardian mode after lightning strike

[pblanco10]

Hi all. Long time reader, first time posting.

2005 225 Optimax

So three weeks ago my starboard engine was hit by lightning, I know this because I was just inside my garage and saw the huge fireball about 5 feet away from me. It found ground and the engine's skeg, nice grey mark in the asphalt. Luckily my garage shielded me, I lost another one of my nine lives. Now for the details and what i've done so far.

I had a local Mercury Mechanic plug in the diagnostic computer. The engine says is guardian mode for unspecified reasons, clearly because of the strike. Does not show any faults. Engine water PSI reads 9psi with just the ignition on and not running, Fuel level shows empty although I have fuel.

Unfortunately the LCD's on both of my tachometers are washed out so I have to get my data from my Garmin


(1) I took the PCM from the bad engine and plugged it into the port engine which is good. The Good engine ran fine with the PCM from the bad engine. PCM is not the problem.
(2) I disconnected the fuel/oil harness from under the cowling, All engine information on the Garmin stopped working. Reconnected the harness and the water pressure reading did not correct itself, engine in guardian mode
(3) I disconnected the water pressure sensor, Garmin gave me a canbus change warning, I ok'd the warning and then a reading of 0 PSI for water. Engine in guardian mode
(4) I reconnected the water pressure sensor, 9PSI with only ignition on. Engine in guardian mode
(5) I took the water pressure sensor from the good engine, and installed it on the bad engine. I still have a reading of 9PSI with only the ignition on. Water pressure sensor not the problem. Engine in guardian mode.

Any ideas based on the above trouble shooting?

[jeffg]

1: remove smart craft plug from engine and rely on beeps.im a backyard merc guy but know optis well.One thing they have is a bunch of grounds.I know this because I have chased many down.Your situation im certain went through all of them.I found some grounds in a opti tide together hidden in the harness.,the shift delay didnt funtion.My instinct would be to change tps from one engine to the other so i wouldnt be worried about it.I would then set my meter on continuity and ground one end to the block.In this mode it beeps on continuity.I would unplug each sensor one at a time and check ground,they all have one.First time you dont get a beep,add a ground wire to block.dont be concerned if ground has a tracer.Tracer indentify there funtion.Before doing anything,start engine and make certain alternator is putting out.A surge will pop the diodes,optis aint happy without juice.Your most fortunate to have a doner engine.good luck.
Unplug smart craft.check alternater.switch tps from engines.check ground on tps first and go on.buy a harness

[pblanco10]

Thank you. I will start with the TPS and ground tomorrow.

[Motv18]

You might have to test the harnes for burned wires.