Mercruiser 496 intermittent alarm power loss

[Freobhoy]

hi all, newbie to the forum looking for any guidance / expertise. I have a Mercruiser 496 mag, 2006, 0w632320 with bravo 3 in a 2006 Maxum.

it runs great, starts fine, idles fine and goes great at cruise and on the plane.

issue I’m having is that once per trip it gives me a single beep alarm with instantaneous loss of power and immediately recovers. This usually happens shortly after starting up (within 5-10 minutes) and has never happened when running above about 2800 rpm.

It only happens when I’m actually underway - never if I’m just running the engine in neutral (well not so far anyway).

when it happens I can see that the Smartcraft gauges stay on but the voltage on the Smartcraft gauge goes to 0volts for a short time and you can see the RPM drop and pick up again.

i have tried checking all of the electrical connections and all seem ok.

i disconnected the Smartcraft gauges the other night and it seemed to get better for a while but hasn’t fixed the problem.

any thoughts on possible issues / solutions.
Thanks in advance

 

[alldodge]

There is a bad connection somewhere

Smartcraft just shows what the PCM is telling it. I'm guessing the problem is on the motor. Battery cable, PCM connector, other connections

 

[QBhoy]

Presumably it’s not the limiter ?

 

[Freobhoy]

Thanks. Don’t think it’s the limiter as it seems to run fine at higher revs, but I guess it could be a PCM fault

I’ll check all the connections again.

I’m starting to think it could be ignition switch or harness

 

[morgans707]

I just started having the same problem yesterday. Did you ever find a resolution to this?

 

[GA_Boater]

I just started having the same problem yesterday. Did you ever find a resolution to this?

He left.

Closed.