So... with 1.9 hours on one of my Sparks, anything other than the slightest throttle results in high revs with very little thrust and massive vibration.
Are these the symptoms of a damaged wear ring?
Thanks,
Tony
Happened to me.
Thought I broke something.
BUT it was a wood chip jamming the impeller.
Spark goes into 'limp' mode so you can at least get back.
Seems like nobody bothers to RTFM (page 70).