2006 johnson carbed150 tach reading too high

[sammi]

Dropped my whaler with the above engine in the water yesterday for the first time this spring. I changed nothing over the winter. Upon starting the engine it ran fine but the tach was jumping between 1000 and 2500. I mean within an 1/8 of a second. The motor was idling fine. We went out for a ride and the engine ran fine but the tach was steady and reading way high. Maybe 4000 but the engine was probably only turning 3000. I didn't touch anything over the winter. No new prop, didn't change any settings. Is my tach going bad? Anything to check? Voltage was fine the whole trip but my battery is probably ready to be replaced. Would an old battery have anything to do with it?

 

[cyclops2]

If you can compare your tach with a direct reading mechanical one on top of the flywheel ? Careful !! NO SLEEVED shirt to get caught in the flywheel.

Could be connections loose or corroded a little ?

 

[guyjg]

Spray into the switches on the back of the tach w/electrical cleaner or WD-40 and exercise them back-N-forth...note original setting.

 

[Boobie]

As said above, rotate the pole setting switch on the back of the tach once and then back to the orginial and see what happens.