RPM Gauge drop to zero

[ramrahq]

Hi.

 

First of all great forum guys, just came across it when browsing around the web. My problem though is with my SP470 with 2200 motor. When I do my magneto checks the first one is fine drops about 50rpm but when n switch the second one off the rpm gauge goes to zero. The engine still runs fine and the rpm doesnt drop at all just the gauge. Can the gauge be wired incorectly.

 

Thanks

 

 

[Tomo]

Has the problem just started? or has it been there since RPM gauge installation? Have you installed anything new lately? Ie, radio, new switch, new coil, mag's etc...

 

To me, what's is happening is when you switch the Mag off, you open circuit (turn the signal off) to the RPM, thus Zero RPM, but for that to happen, it's wired up wrong. Have you touched it recently?

 

 

[hfrensch]

Jabiru took the RPM signal of one coil for the tacho on one of their models some time ago, I am sure thats your problem not a major problem as you should hear the engine run rough during mag check. Can be changed by adding a pick up and plates to flywheel and reset the tacho.

 

Cheers Helmut.

 

 

[ramrahq]

Thanks for the replys. I recently baught the plane but didnt notice this when I test flew it. They added a transponder with the last service, this might be where things went wrong.

 

 

[Guest 4aplat]

Hi.First of all great forum guys, just came across it when browsing around the web. My problem though is with my SP470 with 2200 motor. When I do my magneto checks the first one is fine drops about 50rpm but when n switch the second one off the rpm gauge goes to zero. The engine still runs fine and the rpm doesnt drop at all just the gauge. Can the gauge be wired incorectly.

 

Thanks

Hi

 

it depends of the gauge and the sender

 

If the info come from the magnetic sender on the flywhell you're not supposed to go to zero (this kind of sender is independent from the magneto)

 

If the info comes from the alternator --> same thing

 

If the info comes from the magneto (ex mgl gauge) you will have to make a modification on your wirering loom

 

Michel

 

(there is the schematic somewhere in my forum)

 

 

[ramrahq]

Hi Michael. Thanks for your reply. Any idea of where I can find the scematic?

 

 

[Guest 4aplat]

http://jabiru-owner.com/images/pdf/magneto.jpg

 

B1 and B2 are the 2 magnetos

 

CT is the gauges

 

in the middle the 2 switches