Rev counter problem
in General Tech Discussion
10 years ago
I’ve got a problem with my rev counter on my 912 uls engine. The Rotax rev counter has worked fine for years bud now the latest moths it has started to get nervous at around 3500 rev and higher. I think I need some good advice to cure the problem.
The blue/yellow wire from the sensor is connected to the rev counter on the gauge, the white/yellow is connected to the minus on the gauge and to ground and the red one to power / fuse.
If I check the power from the sensor just before it goes in to the gauge (engine on) I receive on
2200 revs 1,4 V
2400 revs 1,6 V
3000 revs 2,0 V
3500 revs give 2,5 V and now the needle on the gauge starts to get “nervous”
If I check the “mags” at this revs they behave ok they sink with roughly 50 revs
If I increase the power on the engine up to 2,7 V the needle goes up to 7000 and stays there
If I switch of one of the “mags” the rev counter behaves normal.
If I change to the other “mag” the problem above starts.
I’ve checked all wires from the sender to the rev counter for any kind of play and haven’t found any.
If I connect my electric adjustable propeller (Woodcomp) the rev counter on the display shows stable values all the time.
When I’m airborne the electric propeller works up and down all the time and I have to go to the manuel regime and to calm it down.
Anyone out there who has any idea of how to solve this.
As I can understand there are some things that can affect the rev counter to act like this.
1 the gauge is out of order
2 The sender is out of order
3 the distance between the sender and the wheel is not ok, in the heavy manual I can read the distance 1H02 anyone who knows what this means in mm?
I have also heard that you can put a resistance in the line of the rpm signal, anyone who knows anything about this?
The blue/yellow wire from the sensor is connected to the rev counter on the gauge, the white/yellow is connected to the minus on the gauge and to ground and the red one to power / fuse.
If I check the power from the sensor just before it goes in to the gauge (engine on) I receive on
2200 revs 1,4 V
2400 revs 1,6 V
3000 revs 2,0 V
3500 revs give 2,5 V and now the needle on the gauge starts to get “nervous”
If I check the “mags” at this revs they behave ok they sink with roughly 50 revs
If I increase the power on the engine up to 2,7 V the needle goes up to 7000 and stays there
If I switch of one of the “mags” the rev counter behaves normal.
If I change to the other “mag” the problem above starts.
I’ve checked all wires from the sender to the rev counter for any kind of play and haven’t found any.
If I connect my electric adjustable propeller (Woodcomp) the rev counter on the display shows stable values all the time.
When I’m airborne the electric propeller works up and down all the time and I have to go to the manuel regime and to calm it down.
Anyone out there who has any idea of how to solve this.
As I can understand there are some things that can affect the rev counter to act like this.
1 the gauge is out of order
2 The sender is out of order
3 the distance between the sender and the wheel is not ok, in the heavy manual I can read the distance 1H02 anyone who knows what this means in mm?
I have also heard that you can put a resistance in the line of the rpm signal, anyone who knows anything about this?
