Tiny Tach question

[ehenry]

I bought a Tiny Tach last year and installed it on my Merc 25 h.p. Works like a champ. RPM's in the 5500 to 5800 range when running WOT. Didn't use my boat any during the winter and when I started using it again this year I noticed a change in the rpm's. With absolutely no changes to the engine or prop at all the Tiny Tach is reading 7400 plus rpm's at WOT. Anyone have any ideas what would cause this??

 

[roscoe]

Re: Tiny Tach question

Lighter boat???

 

[ehenry]

Re: Tiny Tach question

Same boat, same everything.....no chges at all.

 

[FlyBoyMark]

Re: Tiny Tach question

Did you leave the unit out to freeze..there is 5 year lithium battery in it....You might also check to see if any of the wires from the unit are draped across any of the other spark plug wires, additional inductance from other wires will give you eronius readings.

 

[jim dozier]

Re: Tiny Tach question

Try a different prop, maybe your prop has a spun hub. Is the wiring on the Tiny Tach still set up the same way?

 

[kd6nem]

Re: Tiny Tach question

Unless that motor is screaming to the point of blowing itself apart the tach is just reading funny. Look at the pickup wire, make sure it is not draped over another spark plug wire like FBM said.