Rotax 912ULS shakes alot at start

Re: Rotax 912ULS shakes alot at start

by Rick McWilliams » 12 years ago

Rick McWilliams

0 1 0

I had trouble with kickback and rough starts. I changed to the soft start CDI units and it was slightly better. I have a superstition that I might have been flooding half of the engine while turning the propeller to purge the oil from the crankcase. I now advance the throttle when pulling the propeller through. I have not seen a rough start in the last 20 flights.

Re: Rotax 912ULS shakes alot at start

by Stefan Hoecherl » 12 years ago

Stefan Hoecherl

3 24 0

I fly a 912s on a DTA Trike in Africa since 2003, previously I had a 912 (80hp) mounted. The 912s shakes more at low RPM, I too advance throttle on startup to keep it running smoothly. To the "shaking at 50% throttle" : I only had that when iced (in flight).
Once though, I hadn't used the motor for 6 months and it gave me more of those shaking issues (shaking to 3500rpm,it was stored in warm/moist climate). there was a layer of rust on the iron core of the magnetos. Using a fine sandpaper did away with that and shaking was instantly better, but not as it should be. but after another 1-2hrs flying it was gone, and i hadn't noticed it again.
rgds
Stefan

Re: Rotax 912ULS shakes alot at start

by Andre El Ghawi » 11 years ago

Andre El Ghawi

6 23 41

Shoaib,

Did you ever solve your problem? Can you please share?

Andre'

Re: Rotax 912ULS shakes alot at start

by Kenneth Hagesten » 11 years ago

Kenneth Hagesten

2 38 0

I have also had that problem with violent shakings and it occurs most often in cold weather starts. I believe it has something to do with the fuel system. My solution has been to preheat the motor in cold weather.

Also i think i should install a complementary electric fuel pump to use at starts. Does anyone know if that is a good idea?

Re: Rotax 912ULS shakes alot at start

by Roger Lee » 11 years ago

Roger Lee

131 5.38k 5.44k

This shaking can be several things. It could be bad engine mounts, poor carb setup, poor starting technique. Choke or throttle position error at start, carb sync out. these are common cause and should be ruled out, but other influences maybe at play, but best to rule out the quick, common and easy ones first.

---

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell