I've already taken my plane to two rotax mechanics and they both gave up, at least short of tearing everything apart.

My engine is somehow consuming way more fuel than its supposed to.  Sometimes it's normal, sometimes it uses 3gph at idle and 12+ at 5500.

- 100hp Rotax 912uls
- Total fuel consumption has been confirmed many times when refueling
- The problem is very intermittent
- It *seems* to get worse with hot weather (above 30°C/85°F)
- The engine is running perfectly normally and smoothly. It's not actually consuming the fuel. My only guess is that it's dumping it but I can't see that line in flight
- I've checked and replaced the floats
- just did a 200hr where the carbs were taken apart, cleaned, and inspected
- Replaced all spark plugs
- Replaced the fuel pump (this seems to have helped in that the problem occurs less frequently but it's not gone. It's also been cooler for the last 2 weeks since I did that)
- I can usually "fix" it by carefully manually restricting fuel flow. The engine runs the same, but now I'm at a point where it actually can't get more than say 5.5gph and if it needs 5.6 I'm in trouble

Anyone have any ideas? My biggest clue is that it very much seems related to outside temperature.

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