first of all You should get some spare parts as you can get them really cheap nowadays, the only one you will want to stay away from is the new fuel-tank. It has only got a filler tube, fuel-tankvent is a hole!
You can also not clean out rust as it is a chemical reaction, that can´t be stopped.
you´ll want to run these engines with 35%nitro, 10%synthetic oil, 10% castor oil & the rest methyl alchohol ( a.k.a methanol)
works for me!
-mr.charlse