I have a 2010 Sea Ray 175 runabout...

[RML_L]

I have a 2010 Sea Ray 175 runabout with a 3.0 MerCruiser sterndrive.  Many of my gauges are unreliable.  The fuel gauge reads "full" when it is empty or partially full; and it reads "empty" after a refueling, of course!  My oil pressure gauge and trim gauge both seem to be poorly calibrated, with most readings occuring outside the graduation scalings.  Speedometer and tachometer are, surprisingly, seemingly okay.  The boar only has 100+/- hours on her.  Help, please, advice . . . !

[Abiggerboat]

BOAT... = Bust Out Another Thousand$

[Lyle1]

Had the 4in1 gauge and the sending unit replaced. Fuel gauge stays on full until 15 gallons are used then drops to 3/4 on gauge . Spent $880 and problem still exist.

[Captain_Rick1]

RML&L Couple of potential issues you need to deal with. If you have the expertise, then check all the grounds at the gauge cluster down to the grounding bus bar, Then check grounds at the tank sending unit. Disconnect the ground wire, clean, lube (Corrison X) and reinstall. If this does not fix the problem, check the OHM value of the sending unit. Should be roughly a 30-240 OHM output to the gauge. If this is correct, then your gauge is probably bad. If you determine it the sending unit, its probably a ROYCE INDUSTRIES unit and they can be ordered online once you know the exact depth of your current gauge. Good luck....

[HUMPH]

I agree that there may be a ground problem if that many gauges are unreliable. If it were simply the fuel gauge, clean up the ground connections at both ends and see if that helps. If, replace the sending unit within the gas tank. There are different options for the sending units and you don't have to replace with the same type as you currently have.

[Captain_Rick1]

If you are going to replace a sending unit (only if it verified as faulty) go with a unit that has some pedigree behind it. That's why I recommended ROYCE INDUSTRIES. You can get many forv20 bucks but you normally get what you pay for IMO.