I have the exact same setup, 08 Sabre with 150 Opti. I had the same question when I bought mine about the water pressure. I found that the 150 Opti has a high volume, low pressure water pump. Therefore he will not see 25 psi. Mine runs 10-15 when wide open and less than that when just cruising. I even tried lowering the jackplate but it has no affect on it. The 150 doesnt run the water pressure that the big motors do.