Hello all.

During a pleasant evening flight with the Mrs, we dropped down to low level to do some sight seeing. We'd been flying for about an hour at this point in a rented EV97 with a 90hp Rotax912 engine.

During climb out from the sightseeing I went to full power, but after a few seconds of full power the engine started running very rough. I immediately pulled back on the power, as the hairs on the back of my neck went into overdrive and my stomach churned. Thankfully, pulling back the power helped and stopped the rough running.

We were near the field, and on our way home anyway, so I made the rest of the journey, on the edge of my seat, never above 3/4 power. T's and P's were always within limits during/after the rough running. However I didn't check the fuel pressure during the roughness (checked it after once resolved and was fine). Only think I noticed was a fairly low oil pressure, but this may have been due to the lack of power when I checked.

Once on the ground, we did a full power runup and the engine ran fine (although, the prop was obviously not loaded during this test).

I reported it immediately to the owner, who said it may have been vapor lock. He is obviously quite concerned and having it looked at - apparently this was an issue that we thought was resolved.

Has anyone here experienced a similar issue with a Rotax engine? Or any engine for that matter? Any ideas what it could be?

Obviously the engine will be inspected by the club mechanic, I am asking to try and learn from this, I'd like to improve my knowledge of engine issues.

The Mrs never noticed a thing btw, I only told her when we were on the ground 😂😂😅

Thanks!