Re: PSI
I'm not a Yamaha person but since Rodbolt hasn't jumped in yet I will take a stab and suggest 15 - 17 PSI at WOT and 5-8 PSI at idle. The best reference is to note the idle and WOT readings right after water pump replacement. Then over time, any deviation from that benchmark is an indication that the pump is due for service or there are other cooling system issues.
