No RPM rise on soft start
in 912 / 914 Technical Questions
7 years ago
Hi
All
I have a 2year old/250hour Rotax 912ULS that has soft start installed.
For the first year or so, cold starting was flawless, engine started within a few cranks, ran rough for 5 seconds then got a distinctive rise in RPM of about 300rpm and then the engine ran smoothly as you gradually turned off the choke.
At the start of this year, the engine was out of commission for 5 months as an engine frame was replaced requiring the engine to be temporarily removed.
When the engine was replaced a 200hour service was done.
After this, the engine starting was terrible with no distinctive rise in RPM.
The poor starting was exacerbated by a flooding carb and once the faulty float was changed starting was much easier.
Although the engine now starts ok, there is still no distinctive rise in RPM like there used to be.
The soft start wire from the start solenoid coil positive to both the ignition modules has been checked to see that it is connected and that 12 volts gets to soft start input on the ignition modules on start.
Everyone I have mentioned this issue to suspects this wire but it has been checked by multiple people including a LAME.
Any ideas on why the RPM doesn't increase after 5 seconds on starting?
Doug
All
I have a 2year old/250hour Rotax 912ULS that has soft start installed.
For the first year or so, cold starting was flawless, engine started within a few cranks, ran rough for 5 seconds then got a distinctive rise in RPM of about 300rpm and then the engine ran smoothly as you gradually turned off the choke.
At the start of this year, the engine was out of commission for 5 months as an engine frame was replaced requiring the engine to be temporarily removed.
When the engine was replaced a 200hour service was done.
After this, the engine starting was terrible with no distinctive rise in RPM.
The poor starting was exacerbated by a flooding carb and once the faulty float was changed starting was much easier.
Although the engine now starts ok, there is still no distinctive rise in RPM like there used to be.
The soft start wire from the start solenoid coil positive to both the ignition modules has been checked to see that it is connected and that 12 volts gets to soft start input on the ignition modules on start.
Everyone I have mentioned this issue to suspects this wire but it has been checked by multiple people including a LAME.
Any ideas on why the RPM doesn't increase after 5 seconds on starting?
Doug
