I have a 1995 Mercury 90hp outboard on a little Skeeter that I just bought. I put a new impeller in it and a new water pressure gauge with new tubing, that is hooked in the block at the designated plug above the spark plugs. Does anyone know what pressure I should be running? It pees great but no matter what rpm range I am at it will not break 10psi at the gauge. Idle is about 6 and wide open is about 9-10. I have been scouring the web and cannot seem to find a number to put to it. Thanks in advance for any help.