Hi - I'm a newbie to Sea Doo maintenance but I have a friend who will assist me if I run into trouble. I have a 657 X engine running Mikuni BN-38I dual carbs that the previous owner dropped into a 1994 SPI hull. I assume I should be tuning my carbs to match a 1994 XP. With a 1.5 Needle Valve Assembly and a Pop-Off pressure of 16-21 psi, what size Needle Arm Springs should I order. Spec sheets indicate 80 gram springs (at 1.5 N & S) is 38 psi. 95 gram springs are rated at 43 psi (1.5 N & S). Do I order the 65 gram springs ? If the 65 gram springs are rated at 32 psi, how do I adjust for 16-21 psi pop off pressure ? Thanks !!