912S back firing problems + ignition timing

Re: 912S back firing problems + ignition timing

by Robert Lavigne » 14 years ago

Robert Lavigne

0 4 0

Hi Jaap.

Do you only have change the flywheel or also the sprag clutch
at the same time?
Changing both is good but makes us question if the solution is to be on one or the other repair.

Thanks
Robert

Re: 912S back firing problems + ignition timing

by jaap wijsman » 14 years ago

jaap wijsman

1 5 0

Hello Robert,

Due to the fact that during our previous trouble shooting we have experienced many times violent back firings , and while continueing with all kind of error seeking like mixture igntion etc , our sprag clutch has expereinced so many violent back firing that at a certain moment while staring / cranking the engine it sounded like a old fashioned coffee beans shredder.
So coming on the questions if your spragclutch has to be replaced ; it all depents how many violent kick back it might have suffered . When occasionally a few times you might concider to leave it as it is . However if any doubt => replace it also .

Rgds
Jaap
Aero Club Valkenburg Netherlands
www.ac-valkenburg.nl

Re: 912S back firing problems + ignition timing

by Roger Lee » 14 years ago

Roger Lee

131 5.38k 5.44k

Hi Jaap,

You are absolutely right. If any of you have a kick back problem on start up you need to find out what the cause it immediately. Too many kickbacks can indeed destroy the sprag clutch. That requires the removal of the stater / water pump housing on the engine and special tools.

---

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

Re: 912S back firing problems + ignition timing

by Gregoire michel » 13 years ago

Gregoire michel

0 2 0

Hi guys,

I'm very worry with my sprag clutch right now. Is a faulty sprag clutch can cause an in-flight engine failure or it acts only on start-up?

Thank you

Re: 912S back firing problems + ignition timing

by bill martin » 13 years ago

bill martin

10 757 0

Greg,

The sprague clutch is only in use during engine starting. Once the engine is running, it is no longer functioning.

Bill.