How about pouring a bucket of sugar into a Cessna fuel system during
the night. This is what happened in our hangar...
It turned out when the engine stopped during take-off. It was few years
ago and we still don't know who did it.

My guess is that you were operating at an airport with a lot of power
traffic. MITSA had some one pour sand into the oil filler of their
Cessna 150/180 tow plane. It was assumed (but not known) that a
disgruntled local power pilot was the culprit. The engine, of course,
turned into scrap metal after it was started.

Tony V.