I have plenty of power from the battery and starter motor.
So much if I leave it in gear it rolls the car.

But sometimes it takes 5, 10 maybe 15 seconds to actually fire
while other times it fires instantly.
When it takes a while to fire up, it always smells rich, like as if I'd just spilled some petrol?
What's the cause? Can it be easily fixed?
I'd rather not waste petrol due to poor starting.