What PSI did the stock blowers run ?
If you ran 5 psi on a small blower turning it fast , and 5 psi on a big blower turning it slow , you didn't really change anything . The only advantage would be less heat build up . If you don't change the heads or the cam or the cubic inch , you are not getting more volume in . Pressure is pressure if all else is the same . Adding more carb to the same mix may have just screwed up the air fuel ratio . Also 34 degrees is too much for blowers in offshore boats . You may be detonating ,slowing it down ..... Just my .02
Good luck !