Reinell Tach reading too high

[bstig60]

I have a 1990 Reinell 17M with a 2.3 liter 4 cylinder Ford engine and an OMC Cobra outdrive. The engine has Mallory ignition and runs well. Sometimes we will be running along at about 3500 or so RPM and the tach will read 5000 and above. Other times is reads correctly. Wiring on the tach is tight. I am not sure it the source for the Sensor lead is on the coil or comes off another location. This is a factory installed system. Any thoughts would be welcome.

 

[hosteter]

Does not the tacho pulses come from altenator?

 

[Bondo]

Ayuh,... The tach should get it's signal from the coil's (-) terminal,....

My guess is, yer tach is dyin',....

If there's a switch on the back to set the number of cylinders, move it from limit to limit, then back where it belongs,....
Many times you can get one more lap outa it that way,...

 

[gm280]

I have to agree with Bondo thus far. You could also be experiencing cross talk depending where the wire is run from the coil. If it is parallel with other high voltage spark wires, you could be reading cross talk from them depending on weather and/or moisture conditions and wire degradation. JMHO!

 

[bstig60]

Thanks for the replies. I will check the wiring again and also see if the tach has an adjustment on the back of it. This is the factory installed tach, so it may be going south for the winter. Are these Medallion gauges or something else?