today i started my 4.3 mercruiser after a long set -up. i had a water pump installed before the lay up. the motor started fine,as i was looking at the out drive ,i noticed ..no water coming from the exhaust port. i let it run for approx. 5 mins. till the temp . gauge started to move . still no water exhausting so ,i shut it down. my question is, does it need to run longer for the thermostat to open or should i see water flowing immediately? which water pump would be the cause of no flow?the one in the lwr.unit or the one on the engine? thanks for any help.