My ford tractor has a button on the injector pump that when pushed increases the fuel injected at idle to help cold start.
in practice I found that not useing it and cranking the motor for 10-15 seconds with the stop pulled out and then pushing the stop in gave instant clean starts, wereas useing the rich start button quite often just made lots of white smoke out the exhaust till the battery was wound flat- flooded diesels wont start!!!!
Stewart