it works great in 503's and 582's. Everyone in my area is switched to it. No more carbon build up and when you "decarbon" it's more like wiping out the exhaust ports and inspecting than scraping carbon build up.

The second best alternative is AV-2 from CPS, it's a hybrid synthetic/natural blend. I had a 503 that was over 800 hours using it and when I pulled the head/crank to do a full rebuild, it didn't need it. Could have gone another 100 hours at least. AV-2 is good too. I'd still use Amsoil Interceptor in whatever 2 cycle engine I own from here on out.

one word of advice, even though Rotax says to use Pennzoil, DONT!