Automotive Brake cleaner works too. As its made to be sprayed onto aluminium brake components which house rubber "buckets" etc I have found it to be safe on my RC car engines etc.

Another one which is an aussie product although expensive if you want to bath the engine is "Solvit Organic Citrus Clean"

This stuff will remove ANYTHING! It removes silicone and Sikaflex!! I have never seen anything remove Sikaflex until this stuff came into where I work. Be careful around paint etc.

I sprayed this on an old OS 46AX muffler and the buildup just ran off it. Wiped it with a rag and it was like new.
It will also remove dry and wet epoxy residue and thin CA smears. I have wiped it over an old plane wing to see if it will lift the covering and it didnt budge. I wouldn't spray it directly onto the surface tho as it will remove the aforementioned glues if left to pool around hinges etc I should imagine.
Amazing stuff. (No I dont work for them )

Reading the contents it contains Ethanol 49%. I am guessing it contains citric acid as well.
Smells like oranges too which is cool