Trouble starting when cold

[Dvalcik]

Difficulty starting my 912 when cold. This just started happening, I sent my carbs off to lockwood for the 5 year service. They came back and I installed them today. I still had problems starting, eventually got it going, sync'd the carbs and set the idle. Things looked good and started no problem when it as warm.

Let it sit for 4 hours and tried it again (no Joy). The Video was taken from on my iPhone.


http://www.youtube.com/watch?v=A4g5kJnuFcM


I did check the choke and it is working, still no good. It seams like the starter disengages after the hint of it wanting to start. I have been reading about the Sprag clutch and wonder if that is my problem.

Any help would be appreciated in trouble shooting the problem.

[Ueli N]

Looks like a "Soft Start" problem.

[Piper J3]

You might want to ask here.... http://www.rotax-owner.com/en/rotax-...ical-questions

[Dvalcik]

Originally Posted by Ueli N

Looks like a "Soft Start" problem.

I do have softstart modules, runs good after she starts. Just issues cold

I am calling Lockwood tomorrow

[JBPILOT]

To me it sounds like the starter Sprague clutch is failing. The starter motor seems to run a bit after it kicks back some, then engages some and stops the starter. How many hours on engine ? How long has this problem existed ?

[BigJohn]

That does not sound good at all. I wouldnt crank it any more until you diagnose the problem, you may do additional damage.

I agree with checking voltage. Maybe even stick in a known good battery (or jumper to one) to eliminate a weak battery as a cause.

[AJSWA]

Originally Posted by Dvalcik

Difficulty starting my 912 when cold. This just started happening.

Any help would be appreciated in trouble shooting the problem.

How many hours do you have on the engine?

Have you checked the gearbox friction torque value?

See maintenance manual in the following link on how to check friction value,
http://avsport.org/acft/Rotax/Line_M...ual_d05562.pdf
(Reference page 173 on or 3rd page from the end of the manual)

If the friction value is too low it can contribute to this type of starting problem.

[Dvalcik]

Talked to Lockwood and they confirmed what I thought. Sprag clutch, I'll be pulling the Rotax over the next couple of weekend.

He looked at the video before we talked and confirmed the issue. He said you have plenty of power, plus I had already confirmed it last night.

[PilotBrent]

Originally Posted by Dvalcik

Talked to Lockwood and they confirmed what I thought. Sprag clutch, I'll be pulling the Rotax over the next couple of weekend.

Ahh, so sorry Dave. PITA for sure. What hours on the Hobbs/TACH? (ie close enough to get the gear box inspected at the same time at least?)