Single cooling is enough for a stock motor with bolt ons.
Line from pump to through hull fitting.
Line from bulkhead to exhaust manifold.
Water then runs through the exhaust manifold, into the cylinders, and out of the head. (If using stock head, cap the 1/8" outlet).
Line from the head to exhaust headpipe inlet.
Water runs through the headpipe.
Line from headpipe outlet to T fitting.
One leg of the T fitting to the exhaust stinger, other leg to pisser.
At this point you can play around with a restrictor after the T. I like a full waterbox to keep it quiet so I put a 4mm restrictor on the pisser leg of the T. Some people run a restrictor on the stinger leg of the T for better throttle response, but you must ensure that the stinger gets enough water to not melt the rubber hose in that configuration. I never ran it that way because I never noticed a difference in throttle response anyway.
The sizzler I had had 3 holes for cooling elbows on the headpipe. I used only 2 for this configuration. Water can flow either direction through the headpipe. I usually go back to front.
