Tach Erratic

[Skystrider]

I have a 180 with a Jabiru 3300. The tach is fluctuating several hundred RPM rapidly. The engine is running smoothly. Any suggestions?

 

[skysailor]

Do you have the recommended resistors in the RPM sense leads? If you do not have any resistors, you should refer to the install manual to find the value recommended. If you have them installed you may need to increase the value of the resistance.

 

[jakej]

Skysailor & Skystrider
There are no recommended resistors for the Jabiru engine however I've found 100 KoHm to work well on one of the Alternator output wires

Jake J

 

[Skystrider]

Thank you for the suggestion jakej. We are also having a problem with the radio having a great deal of static. Then we realized that the tach being erratic and the radio static happened only when the stobe lights were on. We are going back to verify that as soon as we have a chance. If true, I wonder if your suggestion might solve both problems. Or we might have to reroute the stobe wiring to provide some separation from the wire bundle.

 

[jakej]

What type/make of strobes do you have ? Is the drain (shield) wire grounded at the strobe power supply end ?

Jake J

 

[Skystrider]

Jake J, We have an AeroFlash Signal which came with the Zenith 701 kit. The power supply is located near the signal at the end of the wing and is grounded (rivet) within inches to a terminal wire designed for that purpose. There is a grounding braid positioned between the cover and plate on the signal itself.

 

[jakej]

I'd try adding a ferrite core to the power input wire - simple, cheap & hopefully effective

Jake J