Engine shake at shutdown-Procedure Suggestions

[Pmerems]

Attention all Yoda?s out there with vast experience with smooth engine shutdowns.

What is your best shutdown procedure for a smooth engine shutdown?

I have been flying my RV-7A (IO-360 Vertical Induction, CS Hartzell) for over 3 years and I always believe my engine shakes more than other during shutdown. I tried several different techniques but most of the time the result is about the same. I haven?t tried shutting the mags off just before the prop stops which some have mentioned but I was hoping for some suggestions.

Thanks,

[cajunwings]

Try holding the throttle firmly against the idle stop when you pull the mixture to cut off and hold it there till the prop stops. Not sure why but Mooneys with similar engine/prop setup shut down much smoother using this technique.

Don B

RV 9 Rebuild in Progress.

[rhill]

What engine mounts do you have? The Lord J9613-49 has silicone dampeners to dampen shut down shakes,not cheap at $150 a corner these might help.
RHill

[Ron RV8]

I have found, particularly with our Mooney (O-360 A1D), that shutting down at about 1200 rpm gives a cleaner shutdown. At idle it gives a pretty good "wet dog shake".

The RV (Aerosport O-375 A1A) doesn't seem to shake as much but shuts down quicker at above idle rpm. Maybe the lighter Catto prop?

[60av8tor]

Originally Posted by Ron RV8

I have found, particularly with our Mooney (O-360 A1D), that shutting down at about 1200 rpm gives a cleaner shutdown. At idle it gives a pretty good "wet dog shake".

Same here - I pull the mixture at 1000 RPM and it seems to shake less.

[Remag]

You might just have good high compression. Once the fuel is denied to the combustion process, higher compressions will result in a more sudden stop. Sit back an watch a 912 Rotax shut down some time. With 10.5:1 compression, the shutdown will usually rattle a couple of fillings out of your teeth.

[AaronG]

I increase the rpm over 1000, and pull the mixture. Just as the engine starts to quit, loose rpm, and shake, I completely close the throttle. Really helps on my carb engine, a smaller but still noticeable improvement on the fuel injected engine.

Aaron

[Frank Smidler]

Another vote for pulling mixture at 1000 RPM. I have an 0-360-A1A with a wood prop (heavier metal prop may react differently). At 1000 RPM I pull the mixture and don't touch the throttle. Always a smooth shut down. If I pull the throttle to idle before pulling the mixture the engine will shake a lot.

[Mark Dickens]

Reviving this old thread...I was reading my owner's manual for my AFP injector and it states that pushing the throttle forward while (or just after) you pull the mixture to ICO smooths the shutdown. In 33 years of flying, I had never heard that and tried it this morning in my Bonanza...seemed to really help. I was wondering if anyone else had experience with this?