NMEA Network issue

[Three Seasons]

NMEA network issues -or- so I think. Starting last fall and started again last week after splashing. After starting both motors somewhere between 1 and 6 minutes i hear a beep and simultaneously the port motor quickly misfires and all gauges (including Smart craft) go blank for 10 seconds. Does not happen again until i restart the boat. Hot or cold does not make a difference and happens on 80% of start ups.

Thinking loose plug or ground, your thoughts would be appreciated, where do i start?

 

[dtfeld]

While not exactly similar, I have a similar issue with my setup, so maybe a good data point. Regardless of what order I start motors, when I start my port, all Electronics go dead/restart. I've solved by turning everything off then on after starting.

However, I think the port batteries are not as strong or there is something in the wiring design that the battery solenoid drops out for just a slit second.

 

[alnav]

Doubtful if your problem has anything to do with NMEA; sounds like all Smartcraft. Lots of problems with systems your age seem to have been solved by tracing out the wiring from your display and reseating the connectors, cleaning them if necessary.
Also, FWIW, when I first bought my current boat, which had Smartcraft of about the same age as yours, the dealer was emphatic that I should always start the starboard engine first, then port, or strange things might happen.

 

[ttmott]

Doubtful if your problem has anything to do with NMEA; sounds like all Smartcraft. Lots of problems with systems your age seem to have been solved by tracing out the wiring from your display and reseating the connectors, cleaning them if necessary.
Also, FWIW, when I first bought my current boat, which had Smartcraft of about the same age as yours, the dealer was emphatic that I should always start the starboard engine first, then port, or strange things might happen.

No need to "start" one before the other but have both ignitions on and allow the Smartcraft system to boot up. The starboard is usually the side CAN P carries it's data (rudder position, fuel levels, etc) and having that SIM up and running when the data system display boots helps. However, I was curious why technically the Starboard needs to be on before the Port - I've tried to get the system to fault and cannot. I think it is a game of Broken Telephone.

 

[swaterhouse]

While not exactly similar, I have a similar issue with my setup, so maybe a good data point. Regardless of what order I start motors, when I start my port, all Electronics go dead/restart. I've solved by turning everything off then on after starting.

However, I think the port batteries are not as strong or there is something in the wiring design that the battery solenoid drops out for just a slit second.

Your issue is different and super common. Your electronics probably run off the port engine batteries, when starting there is enough of a voltage drop that the electronics shutoff. Two common solutions are to always use the "emergency start" or do as you are now and wait to fire up electronics before starting.

 

[Nauti 97]

Your issue is different and super common. Your electronics probably run off the port engine batteries, when starting there is enough of a voltage drop that the electronics shutoff. Two common solutions are to always use the "emergency start" or do as you are now and wait to fire up electronics before starting.

my 97 370 did the same thing even with new batteries. I just made it part of my routine to start the engines before turning on the Electronics.
I talked to a couple of electronics guys over the course of a few years, and they both told me the same thing as mentioned by swaterhouse. The electronics are wired to the port Batteries and it is Voltage drop when cranking the engine. They both told me it is a good idea to have the electronics off when starting the engine.