Shutdown engine shake

[Rich]

I found that pulling the throttle all the way to idle right before shutdown it spins smoothly down like an electric motor. MT prop FWIW.

[Roxi5m9]

Same here! Nice to hear that mine isn’t the only engine that shakes so badly. The only DA40 I have any experience in is mine. Do they all shake this way? A byproduct of such a rigid fiberglass form?

[arksat]

Rich, to be clear, do you mean at first you pull the mixture to cutoff position, then throttle to the idle just before the engine to stop?
The shake has been annoying and concerning so I definitely want to give it a try!

[Rich]

Remember the mags are still sitting at 25 degrees BTDC. Mixture is typically about 1/3 back anyway taxiing in. First I pull the throttle to idle (mine idles at about 700 RPM). Then pull the mixture. The idea is then the engine is getting very little air as well as fuel and I want to minimize the possibility that any cylinder fires during the shutdown sequence.

Also, at this reduced RPM, there is less residual momentum in the engine/prop to keep it turning for unnecessary (and undesirable) revolutions.

[Rich]

Another factor in using idle RPM for those of us with just magnetos: The sparks are weaker at 700 RPM than at 1100 RPM and less likely to fire a cylinder.