significant rpm drop on one Ignition

[NorthIdahoAvidflyer 374]

I took my first cross country flight yesterday evening. I flew 43 nm to Sandpoint Idaho. When I ran up before leaving one of my mags dropped 200 rpm and the other dropped 1900 rpm. I notices it was not running as smooth at lower power settings also.

Where do I start looking for the issue???

[Allen Sutphin 705]

As always, start with the plugs. You didn't say what engine you have. That much of a difference, I would have stayed on the ground until I found the problem.  'If its not right, no flight' keeps you alive.

[NorthIdahoAvidflyer 374]

Rotax 582 GH DCDI

[akflyer 1427]

Plugs is where I would start.  With the inverted engine, we tend to foul more plugs than the upright engines as the oil pools and gathers in the plugs when it sits.  Plugs are cheap and are always in my tool bag in the airplane along with spare filters, a few assorted nuts and bolts, cotter pins crimp connectors etc.  We have spare plug caddys on the sleds for a reason.

 

[C5Engineer 1170]

Ive had less overall plug issues with the Iridium NGKs. BR8EIX

[Turbo 162]

Just a question:  Do you carry extra plugs just so you can easily swap in clean ones?  These one-piece items don't wear out (well, they do but only very slowly), but they do crud up if engine conditions aren't right.  One could just as well carry the wherewithall to clean & maybe gap them.

Edited 5 Oct 2018 by Turbo

[FredStork 453]

I have a small toolbox in the plane on longer trips with a set of fresh plugs. But here in France it is more important to always have a pair of old and damage plugs in case you want to do a back country landing and get caught... Oh, I had to land, the engine didn't sound right... dang, look at those plugs... 

Edited 5 Oct 2018 by FredStork

[Guest]

Damn Fred, that is some good thinking! 

[NorthIdahoAvidflyer 374]

That is a great idea Fred. I will steal that. 

The new plugs are in and all is well. 

[Matthewtanner 44]

Fred that’s why I carried a bunch of chicken bones while flying in the Blackhawk, and right before the crash I’d say “who let this chicken loose in the cockpit!?”....if you survived they pull the tape and your free, if you don’t survive the crash, it will make for an interesting accident investigation.

Edited 6 Oct 2018 by Matthewtanner

[FredStork 453]

Oh Matt, that gave me a good chuckle !