Starting 912s

[Massimo]

Hi All,

Im battling to get my engine started. Seems like there is no spark. Did start before but now just turns over. My earth is connected directly to the engine mount and i have scraped the paint off. Any other suggestions or thoughts

[Greg]

1st put petrol
2nd switch electrics on
3rd turn key
4 see what happens
if still no spark change personality or battery

good luck

Hey there hope all is going with the build

[Morph]

I am having the same problem, it is driving me absolutely nuts.

viewtopic.php?f=13&t=9736

The latest I have discovered is the battery appears stuffed. I can charge it up to 14.5 V, but on the first crank I can see the voltage being drawn down to 12 or even 11.5 V. I had found that a new regulator had quit and I managed to get another one from Chris Liebenberg (once again thanks Chris) This one I installed and had to jumper from a car directly onto the battery to get her started. This you can only do if the boot cowl is stripped off. At least the regulator is charging the battery now.

The next time I had everything closed up and ready for flight. I have extended the positive lead so I can jumper it or charge it without removing the cowl. This time she just would not start, no matter what I tried. I am seriously pissed off with this plane at the moment. The problem is I cannot draw enough current via the jumper leads to get her to start, even though she is cranking over.

So fork some more money out for a new battery and let's see.

It appears that the 912 needs a nice healthy, 16ah battery minimum.

[German]

Morph I had the same problem with my previous 100hp.After I bought the second battery and still not enough cranking speed I laid a second battery cable and all problems solved.Ok that was on the Tecnam where the battery sits at the back of the fuselage and you get a hell of a voltdrop.

[Stephan van Tonder]

What kind of hours on these engines? Guys really don't believe me when I tell them this but we have now learned from experience. As soon as the 912 in the cheetah struggles to start you get Gideon in to redo the slipper clutch / backlash on the box. Soon as it's done the engine starts first time and it is also smoother once done. Looks like basically every 200 hours or so this seems to happen. If you have a case where the motor seems to kick back without taking you can know this is the issue.

[Morph]

150 hours,

In my mind I am trying to figure out how this will affect the starting. I do not have a slipper clutch on mine. I will look into it

[Stephan van Tonder]

I found that advise on a rotax site after the first time we had trouble. We had the box redone and voila - the starting trouble disappeared. Two weeks ago it started with that same again - had the box sorted and - gone are the starting issues again. It's the prop cycle that fights the kickover.

Ok here it is - just page down - it's well towards the end on page 10. http://www.rotax-owner.com/support/FAQs.pdf

[Low Level]

Two weeks ago it started with that same again - had the box sorted

Stephan

What is being done ? Is it something that wears that have to be replaced, or is it just an adjustment ?

[Massimo]

My engine has just been completetly redone by Gideon. It may be my battery as ive been using it alot over the past few months to test the instruments so now im charging it and will try again.

[Morph]

We had the box redone and voila - the starting trouble disappeared.

Any idea on how much this costs?

Two weeks ago it started with that same again

How long was it working fine before it started playing up again?

[Stephan van Tonder]

Ooo first time was R8k. Haven't asked what the last one cost Andy and I'm not totally sure what all was replaced. There basically was roughly 200 hours between.

[Massimo]

Happiness is...a running motor, and i now have one.
After doing all the reading on the forum, i put my battery on charge and found it was only 20% full, hence not enough to start the motor. Apparently these motors need to turn at 1800rpm just to generate a spark. So i connected the fully charged battery and in 3 turns she started up. Pure bliss

[Bugwar]

If all else fails RTFM

[Boet]

Minimum size battery for the 912 is 19Ah.

[Massimo]

So you telling me that A. Engines ripped me off by selling me a 18ah battery knwoing full well that its was for a 912s