Fuel gauge lost accuracy.

[winston]

When I changed from a 50 Honda to a 60 Mercury fourstroke the Honda fuel gauge which did read accurately has now lost its accuracy. I believe the fuel gauge was originally wired through the control box but with the new motor they wired the gauge to an auxiliary switch. they gauge now reads more than half full with only 10 Litres in the tank. They tank apparatus has not been touched. Any ideas? Thanks in advance, cheers Winston.

[wardy40]

Winston, when you say "Honda fuel gauge" is it an electronic unit with digital readout or the older needle type ?

[scottar]

Could be coincidence or it could be that the installer has removed a required connection that was a part of the Honda harness and has missed putting a replacement in - possibly a ground/negative. If you aren't too familiar with electrics possibly best to let your installer sort this one unless you know someone.

[winston]

Wardy, its a needle type. I have let my mechanic know but and they will look at it during the 20 h service but was hoping that it might be a quick simple fix I could manage myself. Cheers Winston.

[Spaniard_King]

Did you not get a fuel gauge with the Merc?

[winston]

No Spaniard_king, since it was a repower I kept the gauge as it worked well. I do have the smart craft tacho so I know how much fuel I have used but didn't foresee a problem with the gauge. Cheers Winston.

[wardy40]

Winston, with the mechanical needle type gauges there are two types of sender units with resistance either 10-180 ohm or 30-240 ohm.
Your gauge will be set up for one or the other (usually written on the gauge somewhere). If the gauge and sender are different (resistance wise) they normally put a resistor network (a couple of resistors in a heat shrink tube) inline at the rear of the gauge to compensate. I wonder if yours had one on and it was removed.