Hello everyone, this is my first post here . Looking to get some help. I just purchased a 1978 Bass tracker with 1978 40 hp mercury. I started it last night with muffs on and no water came out tell tale. Previous owner says he replaced water pump in July and showed me the receipt where he had indeed bought a water pump. My question is does this model have a thermostat of any kind . Serial # is 5174633. Thank you for your help and if you can direct me to a good online parts place I would appreciate it. What manual is best for reference?