912UL Engine vibration on throttle back

Re: 912UL Engine vibration on throttle back

by MARK JACKSON » 12 years ago

MARK JACKSON

12 332 11

Hi Roger

I hope it keeps going :-)

I will be happy with 4000 hrs.

As a point of interest, do you change the plastic washer and ring halves when doing a service, or do you go on condition.

Also, when pressing the gearbox, how many tons do you press as a maximum.

Mark

Re: 912UL Engine vibration on throttle back

by Roger Lee » 12 years ago

Roger Lee

131 5.38k 5.44k

Hi Mark,

No reason your engine should see your 4000 hrs.

I always change the plastic washer and depending on which inspection the split ring too, but not every time I pull the box. I'm sure Rotax would like it done every time. Kind of like replacing Nylock nuts with a new one every time. CYA

I don't measure the exact tons of pressure, I can usually feel when I bottom out. I'm not a heavy handed type and I try to make my split rings a tight insertion. Most of my gearbox re-shims come out to be right around 475-490 in/lbs.

---

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

Re: 912UL Engine vibration on throttle back

by Kevin Stewart » 12 years ago

Kevin Stewart

5 184 0

Is there any way to determine if the gearbox is worn before removing it? Mine does not have a slipper clutch. Can I put the crank locking pin in place and then measure the rotational play at the prop?

Re: 912UL Engine vibration on throttle back

by MARK JACKSON » 12 years ago

MARK JACKSON

12 332 11

Hi Kevin

Unfortunately not. You will have to remove and strip the gearbox to inspect the prop shaft spline condition.

I would suggest doing it from a piece of mind point of view, if it is worn, the more it is worn, the quicker it will wear if you understand what i mean.

Mark

Re: 912UL Engine vibration on throttle back

by Kevin Stewart » 12 years ago

Kevin Stewart

5 184 0

Bad news folks :(

I removed the gearbox and sent it away for inspection and unfortunately the prop shaft splines are worn. I know that I have no choice but to have it rebuilt but I have been offered the choice of rebuilding it as it was or fitting a slipper clutch.

The cost of either option is truly eye-watering, it is over £1k or £1k5 for the slipper clutch option.

It has been suggested that the slipper clutch will make the engine idle smoother and will help to reduce the wear on the gearbox.

I am open to suggestions/advice on which option to choose. My engine is a 912UL (80HP).

Thanks,

Kevin