Proboat blackjack heatwave 24 water outlet 10 minute free mod 

10 minute mod and get rid of about 6 inches of tubing on each side for less resistance in the water cooling system.
I did place a piece of tape on the bottom of both of the original exit holes through inside the hull and dropped a drop or two of epoxy until it hardened from the top. Then removed the tape leaving the holes plugged.