Been chasing gremlins on a 2005 496ho. More/Less it stalls after 10 minutes. I don't believe it matters how fast I'm going. Relays, fuel pumps/lines, map, mat, crank sensors have been replaced. It runs perfect when it runs

Last time out, it stalled, but didn't lose ECM power. I had a diacom connected.. It showed a volt spike from 13.7 to 14.43 when the motor died. It's not granular enough to see what happened first. Nothing else interesting...

But the previous time out, same deal...10 minutes or so...but the 50amp breaker tripped. This is the first time this has happened.

At what point to i start suspecting the alternator?

Thanks!

Start with the basics. Engine needs air, fuel and spark to run.

And when the engine dies look for fuel pressure and spark. Apressure gauge and testing for spark is cheap and easy. You can also pick up a noid light cheap to see if the ecu is telling the injectors to fire.

I've got fuel pressure at idle, but any suggestions for a gauge with a long hose for when I'm 50-70MPH? They all seem to be a foot and a half long....

Definitely dig into your electrical issue.

Cell phone or GoPro videoing
They are not just for youtube or family vids

ALT may be drawing to much current. Could be enough for the breaker starts to trip and then motor dies so it cools back bown and stays connected. Could also just be the breaker