Tachometer readings on DK180 from Jabiru 3300

[aprazer]

I've noticed that this topic has been discussed for the Rotax engine, but not the Jabiru.
Scenario: Jabiru 3300: Flight Deck Dk180; Pulse/Revolution values are set @ 6; tach wired to alternator with 1 amp fuse; Problem fluctuating tach readings on taxi testing.
Readings: At idle 2000+/- RPM -- hand held tack shows 1050+/- 10
    "         As I add throttle RPM drops to 1600 then
    "         Slowly adding more power tach reading comes up then drops until it reaches full throttle and reads 2300 (static should be 2800).      
Has anyone had this problem? If so, how did you solve it? Any and all help will be greatly appreciated!
Thanks,
Mack Kreizenbeck
601XL N990MK

 

[jakej]

Mark
Try a different value resistor from the standard 30 K Ohm - around 100 K Ohm should do it. Try different values up to 120K.

Jake J

 

[dynonsupport]

The Jabiru in this install doesn't use any resistors, so that's not the issue.

I'd suggest trying the other alternator wire. If something is up in the alternator, this may help debug it. Generally these installs don't have any problems.

 

[jaba-who]

Your post made me recall my problems when I set up my Jabiru 3300. Search and look at my original post "Abnormally high RPM with jabiru 3300" in the EMS installation section from a year and a bit ago.

I can't give much advice - when I did my install I recall it was out till I rechecked and corrected the settings in the dynon and then got the catch-all advice from Dynon - to check and ensure all earths had good connections. I think that fixed it.
But as you will see in the posting - somehow it sorted itself but I'm not sure what it was that fixed it. I had the dual problem of the engine running badly from a carby problem as well.

I realize this is not your main problem but just as an aside - With reference to your static RPM -  Don't be too woried if you can't get your RPM up to the full expected 2800 - 2900.

I have never been able to get mine up to above 2690.  I did all sorts of checking, Jabiru themselves kept saying I must have had a dodgy RPM guage (but both the Dynon and the one they supplied were reading the same) and other Jabirus in my area all have similar (not quite as low as mine but all low 2700s.) rpms. We all spent lots of time trying to nut it out and then found out that it is common to have them low.  

A local prop guru reckons its because they have a very compromised "draggy" fixed prop.