SmartCraft engine surge and single beep, momentary engine cut and single beep

R

Rick Sietsema

New Member
Jul 16, 2019
4
Boat Info
250 SLX 2007
Engines
Mercury 496 Mag Bravo III
Took the 2007 SLX 250 with 496 Mag to the dealer to trouble shoot a single SmartCraft beep that will either give a momentary bump in RPMs while at idle, or a momentary engine cut while running around the lake. No codes are being thrown by the SmartCraft system, and all engine components are well within normal operating parameters. When the engine cuts for a 1/2 second the Tach switches to the "Trim 0" display from whichever display I am using.... then flips back to the one I had it on. 2 items I should mention, I replaced one of the 2 batteries this spring. I didn't take any specific steps in doing so, simply removed the bad one with a new one. The pitot isn't sending a consistent signal to the guages, so I'm replacing that next week. Neither is suggested by the dealer to have anything to do with this SmartCraft issue, though I'm putting it out there for full disclosure.
It concerns me to take the boat very far from home given it might develop further issues. Any suggestions?? The dealer is stumped at this point......
 
Same issue Port motor on 496mag 2006 340. Chased it for 2 and a half seasons. Changed 90 amp fuses on both motors, did not help. Took all the harness connectors apart and sprayed with electronic cleaner, no help. Did it again adding di electric grease, still no change. Changed out the manifold air temp sensor, as it was sending faults as well. Changed plugs,because they were due -no change. Changed spark plug wires, seemed to have fixed it. Went on a 250+ mile trip this past week and no issues. The SmartCraft system is VERY sensitive to voltage issues. Maybe one of the plug wires was grounding out? Not sure, but the problem went away after changing the wires on both engines. Check all of your grounds, make sure they are clean and tight.
 
I noticed the system is reporting it's running at 13.2 volt.... a bit high but I didn't think that would be associated with it. I'll review the grounds, they must be under something as they aren't very noticeable.
 
Rick Sietsema said:
I noticed the system is reporting it's running at 13.2 volt.... a bit high but I didn't think that would be associated with it. I'll review the grounds, they must be under something as they aren't very noticeable.
Click to expand...
I run at 13.2 and sometimes 13.5. Been those numbers since had the boat going on 5th season. So not really off I wouldn't think.
 
Thanks for all your assistance!!! I'll crawl around down there this week and find them!
 
It's the 555 pcm that's voltage sensitive. Merc manual states running voltage should be between 13.9 nd 14.7
 
Thanks scoflaw. I had looked it up and yes running should be higher. My idle (700 rpm)voltage is at 13 ish. I am realizing how sensitive the 555 is to voltage changes. Thanks again.
 
Thanks Guys for the input. Seems like all the numbers on my end are in order. Nice to have the reassurance. :D
 
Hello,
I am having the same issue with my 2006 38 with 8.1HO. The system beeps once and resets the engine and gauges. I am going crazy! Have 2 new alternators, new batteries although i put in 4 marine deep cycle. Not sure if that could cause it. Some said you should have deep cycle for house batteries only. I would not think this would matter once the engines are running and alternators are generating the correct volts. I installed a New digital oil sensor because a tech told me they can have voltage issues and cause this to happen. All new wires and plugs on port side. Disconnected wiring harness and did the same steps with contact cleaner. I started cleaning the grounds in the bilge. I swapped computers from one engine to the next. Swapped wiring harnesses. The issue was only happening in frequently and only at idle. Now it happens all the time at idle or underway. Even when both alternators are producing 14.4 volts. The alternator on the port was bad and was charging less than 13 and over charging at 15.2. Once changed it seemed to be fixed. I was wrong. Went out on sea trial. It did not do it underway but once throttled down heading back to the dock. Anyone else have any suggestions other then grounding issues? Any help would be appreciated. I did also talk to a tech and stated there is also another sensor for the analog gauges. I will order one tomorrow.
 
Rick Sietsema said:
Took the 2007 SLX 250 with 496 Mag to the dealer to trouble shoot a single SmartCraft beep that will either give a momentary bump in RPMs while at idle, or a momentary engine cut while running around the lake. No codes are being thrown by the SmartCraft system, and all engine components are well within normal operating parameters. When the engine cuts for a 1/2 second the Tach switches to the "Trim 0" display from whichever display I am using.... then flips back to the one I had it on. 2 items I should mention, I replaced one of the 2 batteries this spring. I didn't take any specific steps in doing so, simply removed the bad one with a new one. The pitot isn't sending a consistent signal to the guages, so I'm replacing that next week. Neither is suggested by the dealer to have anything to do with this SmartCraft issue, though I'm putting it out there for full disclosure.
It concerns me to take the boat very far from home given it might develop further issues. Any suggestions?? The dealer is stumped at this point......
Click to expand...
Did you ever figure out your issue?
Ron
 
Korkie said:
Same issue Port motor on 496mag 2006 340. Chased it for 2 and a half seasons. Changed 90 amp fuses on both motors, did not help. Took all the harness connectors apart and sprayed with electronic cleaner, no help. Did it again adding di electric grease, still no change. Changed out the manifold air temp sensor, as it was sending faults as well. Changed plugs,because they were due -no change. Changed spark plug wires, seemed to have fixed it. Went on a 250+ mile trip this past week and no issues. The SmartCraft system is VERY sensitive to voltage issues. Maybe one of the plug wires was grounding out? Not sure, but the problem went away after changing the wires on both engines. Check all of your grounds, make sure they are clean and tight.
Click to expand...
Please read and if you can comment on my post below. Wondering if your issue ever came back or if it just ended up being the ignition wires.
 
Just finished an extensive upgrade to electronics and steering. Went from SC5000 to VV 703, changed out steering to hydraulic and added Garmin Reactor 40 Autopilot, fresh water flush kits, new 4X4 props, and a bunch of other maintenance items. In the process of removing the old steering, found a SmartCraft cam bus harness coming from engine room that had been butt spliced. I have a gut feeling when it happened as it was not discovered during the survey (or at least not reported) and I had some work done right after the survey. Anyways, this is certainly suspect to be the cause. I also learned it could be the computer on the engine, as I read somewhere that this will occur and that it is repairable. Just cannot remember where I read it, although I do remember the fix was not cheap. I have had this gremlin for 5 years. Just got the boat back in the water this past week and only a few hours on it, so jury is still out.
 
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