11S poor starting

[Karl1000]

Hi, I have a 53 reg twin spark 11S. Everything works as it should and it is now standard except the Y piece. It is fine once started, is surprisingly quick and gives 50+MPG all of the time. It starts fine from hot, but often either takes >10 turns or a couple of attempts to start from cold, or even if left 3-4 hours. Sometimes it starts ok from cold, but not often! Has Iridium plugs and has about 2 year old coil sticks. Has 19ah gel battery in good condition. Any ideas?