I have a 1987 Mercury 20HP 2 stroke motor which has been in storage in a garage for the last 10 years. I finally go the motor started but I am not seeing any water coming out of the tell tale. Per my owners manual, I hooked up the water ear muffs but I am not seeing any water come out of the tell tale. I only ran the motor for a couple of minutes before I became concerned with over heating. How long should I wait before water should be coming out of the tell tale?