06' merc 6.2 with 435 hrs, runs good and then after 20 mins or so cuts out sounding the alarm, acts like the kill teather is pull or key turned off and right back on real quick, doesn't kill the engine.
Have Diacon software, NO faults detected or stored. By looking at the data only thing I can see or find is a voltage drop right before the hiccup occurs, voltage drops from 14.34 to 13.28 then right back up to 14.34. I've replaced the battery and checked battery cables. Any ideas??
Thanks Steve

Run engine with boat in water, or on hose. Move around every possible wire and connection. Mine did something similar once ended up being the # 7 injector plug.

This was while running in the water, ran fine on hose and was fine last year problem started first time out this year from winter lay up.

You have to pull, push every connection. It sounds like you are loosing power to your ignition system. You just have to do this while running.Find it and you will know, the engine will die. Could also be a crank trigger but do what I said first its free.

Check ground wire going to engine block. Also ground wire that goes to the fuse block.

Chris

Power from the battery goes through a small black 90A square fuse block onto the starter.It gets loose sometimes,all you do is tighten the nut &bolt .The ECM555 senses voltage drop and cuts the ignition out randomly.

Good to know, it is definitely something like that. Thats why no codes the ECM thinks you just shut it off.

By chance have you installed a newer distributor cap lately? Then noticed this problem? If so then try another newer dated cap.

No, haven't tried a new cap, have these had problems with the caps? It doesn't backfire back thru the intake like its misfiring just hear the alarm and a quick hiccup

Yes, lots of different problems with them style caps.

Just something different to think about is all.

The newest merc Cap and Rotor Kit part number is 8M0061335.

?, When you first turn your key on before starting, Do you get a beep from the warning horn as a test? If so try this, Hook up a digital multimeter to battery, start engine, read 14.34 volts turn off engine see if it immediately drops to 13.28 then turn key back on and see if horn beeps again. To test this theory quickly like, use the lanyard kill switch instead of the key switch. Your just simulating a possible ignition cut out event to help theorise on what's happening.

Like said above, shake wires with engine running, Also if you have the 10 pin rubber cannon plug between engine and boat wire harness (at engine side) shake it around really good + it should have a clamp on it set lightly. 2006 may have the 14 pin connector, They are not as much of a problem like the rubber plugs but you never know.

Good luck.