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Yamaha square multifunction gauge not reading any info.

CaptjamesCaptjames Pompano BeachPosts: 231 Deckhand
Ok, so I bought a 2005 boat with a 2015 Yamaha VMAX sho 250hp on it.  The SQUARE fuel management gauge is sunburnt and not showing any info, stuck on 38 gallons capacity, and mode and function didn't do anything.  OK.  The SQUARE tach ( 6y8-8350T-01-00) worked perfectly.  Well I took the boat out Saturday and the tach reset once.....but worked fine otherwise......I ran the boat on Sunday and after a few hours, the tach showed a dash for tach, and no info for any of the other scrolls through the different pages no problem.  So I checked all of the connections, even ran 2 jumper wires from the plug on the motor to the gauge and it didn't change anything.  Where do I go from here? Most people tell me that Yamaha ECM's are bulletproof, so I'm leaning towards the gauge being the problem.  Unfortunately I don't know anyone with a gauge I can try right now. If it's commonly a gauge problem, I'll buy one. 


  • finbullyfinbully Senior Member Hixson, TNPosts: 895 Officer
    Did you check current on the original and jumper wires? If you have proper current, (I don't know what that should be) the gauge has likely failed. Also you said you checked connectors but I would recheck with someone who can keep pressure on them while you look at the gauge. Also, all motors do not provide all functions the gauge is capable of receiving.
  • lemaymiamilemaymiami Senior Member Posts: 4,773 Captain
    "the gauge is sunburnt"  tells you all you need to know - replace it (and if you're not back up and going strong - then it's time for a trip to the techs...). 

    As someone in geezer territory who's been rigging his own skiffs for many years I'm not fond of multi-function gauges but well aware that I may be stuck with one at my next re-power.  I much prefer singles for each function since if you lose one function you're stuck with replacing the entire gauge when everything else might be working just fine.  I particularly like a separate water pressure gauge since I do lot of night charters inshore where a pressure gauge might just save that motor if you pay attention and you've just wrapped a plastic bag around your lower unit.... Not reacting until the warning horn goes off can fry a lower unit.... 
    Tight Lines
    Bob LeMay
    (954) 435-5666
  • CaptjamesCaptjames Pompano BeachPosts: 231 Deckhand
    The other gauge is sunburnt, the tach one is not. I don't know the history other than it was working.   I am leaning towards the gauge and probably going to order a new one (IF they're not back ordered).  Yes my mechanic friend put pressure on the connectors, jiggled them a little also at each step while I watched the gauge.  It's a nmea 2000 wire, did some internet digging and you can only test the signal one of 2 ways, hook it to a chartplotter that can show gauges or check for 60 ohms on the 2 wires.  I agree that individual gauges are nice to have, however the new larger multifunctions will show all parameters on one screen. 
  • CaptjamesCaptjames Pompano BeachPosts: 231 Deckhand
    So I ohm'ed the entire NMEA network from motor to the gauges and getting 60 ohms/120 ohms where I'm supposed to all of the way to the gauge plug.  Something beyond my capabilities is wrong.  Called a friend that owns a Yamaha Dealership and he said either main harness or NMEA harness.....he has both I can borrow to try.......otherwise going to drop it off to him and say fix it.........It's a very annoying thing that I've spent hours and hours on with no result. 
  • lemaymiamilemaymiami Senior Member Posts: 4,773 Captain
    Post up how it works out (and what it cost in money).  Folks here will pay attention... 
    Tight Lines
    Bob LeMay
    (954) 435-5666
  • CaptjamesCaptjames Pompano BeachPosts: 231 Deckhand
    I will.  I own a Yacht Management business and know 3 Mercury dealers REALLY well, then just remembered I know 1 Yamaha dealer really well (just don't deal with Yamaha's much).  Spoke to him, he said either a bad NMEA harness or bad main engine harness (don't think it's this).  He has harnesses he can loan me to test......if that doesn't work, I'm just going to drop it off........
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