Up until two winters ago we had a lot of problems starting our 0-200 and have no primer. Since then we have stuck to the following procedure and it has started instantly every time for the last two winters:
Place a fan heater under the cowl for at least 30 minutes (have a cup of coffee) Apart from slightly warming the oil this also warms the induction system. With the carburettor below the engine and a cold induction system, the fuel vapour tends to condense before it gets into the cylinders.
Remove fan heater and secure cowl.
Mixture to rich, fuel pump on and pump throttle six times (no primer)
manually turn propellor through 8 blades.
Pump throttle twice.
Start. It usually starts in less then one turn.