[fluid]

What would make my RPM gauge read about 1-1.5k rpm's higher than normal? I know from my boat speed and sound of my motor about how many rpm's the motor is turning, but my gauge is readin high.

By the way, it's a 2002 Mercury 150.

 

[RAR]

Prop wear? Are you fishing in shallow water or running through the flats?

 

[fluid]

No, this just happened from taking the boat out last week, everything normal, till going out yesterday. One day fine, the next day the gauge reads different.

 

[capn_billl]

Check wiring, a loose connection can give faulty readings low or high. check switch on divider 4,6,8 cyl. Is it an electrical or mechanical tach?

 

[Pocketfisherman]

Usually it's moisture shorting out the switch you set on the back of the tach. The positions on the switch correlate to how many poles are in your alternator since the tach circuit counts pulses from the stator. Hit the switch with some water displacer like WD40 and cycle it a few time and then return it to it's original position.