496 Mag alarm
 

Looking for help. 2007 496 Mag, closed cooling, mechanical shift. Cruising down the river 3,000+ rpm, alarm sounds, bring throttle back (kind of quick) and engine dies near neutral. Tried to restart in neutral, wouldn't start. With throttle, it would start. My Navman is hooked into the Smartcraft and all vitals are normal. Get back on plane, alarm sounds (two beeps) and I do the same thing. Restart with some throttle, get back on plane and monitor the beeps (two beeps every 60 seconds). All vitals are good, so I continue on to my destination. It was pretty choppy out, so the next morning I check all harness and ground connections (ok). Disconnected batteries for 15 minutes, reconnected and started. The engine (cold), would fire once, the first time, then die. Started it (cold) with throttle and the rpm's were all over the place until it warmed up, then I could idle back, shift, etc. with no problems. Alarm still sounds twice every minute. My mechanic scans the computer and finds no faults. After numerous hours with Mercruiser technician, they send me an AIC (air idle control valve), which does nothing. After further technical help, they send me a MAP sensor, which does nothing. Now they (Mercruiser) tells me it is the computer and has one on the way. But wait! They say that this computer is NLA (no longer available), but one more production run is under way due out on 9/4/09. The engine's warranty ran out in January, the boat has only 118 hours on it. I called Mercruiser customer service for some help/sympathy. What was I thinking? "We feel that we are in no position to offer you any good will." I would decipher that sentence for you, but I am a new member and don't want to get kicked off yet. Has anyone had any problems with pretty new computers? Engine s/n is OW669796. I'm trying to talk with more people at Mercruiser, but apparently they don't want to talk to me, since no one will return my voice mails. Any help would be greatly appreciated!

call 866 496 8181 Ray should shed some light

496
 

ok I know this is going to sound stupid but the same thing happened to me. pull the ignition switch out on the dash the red hot wire may have come loose. my boat would die in rough watter. Im not saying this is it for sure but just check it.

I had a Chevy Tahoe that would start, die, restart, run ok, die, then run ok. This happened two or three times, over a month, ran fine otherwise. The last time, I called the dealer, under warranty, and told them to come get it. They kept it a day and said all they did was replace the battery and could not find anything wrong with it. Never had another problem with it after that.

I want to clarify a couple things. The engine does not die under power, but has a hard time starting and idling when cold. Once it is warm, it does okay. Power all the way up to WOT is great and does not ever die, although the alarm will beep twice every minute regardless. It has never gone into guardian mode. Went up to the marina last night and checked batteries, and all connections, which checked fine. I have a Navman GPS that is connected into the Smartcraft and it can read faults and fault history. One said "Engine data fault". Another said "Fuel Level Sensor Fault" (which details explained high input value), but I don't think this is it since it showed this fault at 100.6 hours and I have 121.8 hours. I disconnected the TPS (throttle positioning sensor) and sure enough, a fault came up "TPS1 Low Input Value". So I need to figure out what the "Engine data fault" means.