Fuel Gauge sending unit?

[Deleted]

My 2003 SV 2100 cc has the original Sea Pro gauges.  The fuel gauge has power and goes to full when motor is on.  However, it never budges off full.  Is it the sending unit on the fuel tank?  Is this an easy fix?  I spoke to my mechanic who of course has to see it.  I'm willing to do it myself if not too involved.   Also, the tach just quit working after a day of bouncing around wildly.  The boat was re-powered in 2011 with a Yamaha F-150. I'm wondering if the Yammy multifunction tach is worth the $300?  It has a cumulative and resettable hour meter, engine trim and I believe other warnings as well.  Funny that the original speedo still works. Aren't these usually the first to go? Thanks for the advice 

[Simple Man]

Welcome Snook Hunter. If the Yamaha gauges are anything like the Mercury Smartcraft gauges (and I bet they are), yes they are worth the extra money.

[Deleted]

I took my sending unit out just the other day in my sv2100 (2007). It was simple for me. 5 bolts and had easy acess.  Once out. I was able to move the sending unit with my hand and verify guage operation.  You can also snip red wire from sending unit.  This should send the guage to empty.  Grounding it will send guage to full. This will help determine if the prob is sending unit, guage, or wiring.  Remember that the sending unit works by changing the resistance across the two wires.  Good luck SH.

[Deleted]

Okay, here's what the mechanic says: He thinks that the sending unit and gauge are working and that the tank is just about full.  I've only had the boat a short while and put 20 gallons in twice and 15 gallons once.  Assuming that the tank was full when I bought the boat, shouldn't the gauge read between 2/3 or 3/4 full if it's 20 gallons down? I believe the 2003 sv2100 has a 70 gallon tank?   He suggested that I run the tank down and see if the gauge shows any movement.  I topped the tank off on the way to launching and could only put 7 gallons in. The boat has the tube style sending unit.  Good news was no charge for checking it out and I found out my motor only has 62 hours on it!!  Please see my next post about a jack plate. Thanks!

[acdaddy0]

I recently had that problem and found to disconnect wires from guage and ohm between them to read your sending unit. Should read 30 ohms full to 250 ohms empty. If it reads in that range it is your guage that is bad. If it is outside of that or open then you either have a bad connection on sending unit or a bad sending unit. Mine was a bad connection on sending unit ground wire. I pulled sending unit and cleaned plate where ground hooks up. Gauge works great now. I had easy acces to mine but if you can't easily pull it you can clean up connections on tank and that will work as well.  Someone had allready cut an access hole over it.