the spring thing is a starter, wind the prop backwards and let go. also makes sure the engine starts and runs in the correct direction, the reed valve engines have no problem running backwards.

the cox engines also need a lot of oil, 20-25% and preferably all castor.

if you need more info then go the [link=http://www.rcuniverse.com/forum/%26quot%3B1%2F2_A%26quot%3B_%26amp%3B_%26quot%3B1% 2F8_A%26quot%3B_planes_%26amp%3B_aircraft/forumid_70/tt.htm]1/2A forum[/link] and you'll find everything you ever wanted to know about cox engines.


dave