I recently had my 250SL re-tuned because it was emitting a lot of black exhaust. But I think, the re-tuning is still slightly off. could someone tell me what a suitable range of revs should be?

Currently, the tachometer shows 1300 when the engine is cold and approximately 750-800 once warmed up. However, this takes about 5 minutes which I think is odd considering I live in the tropics - constant temperature of 28-34C.