i have a 1999 25 hp 2 stroke mercury motor and ive had it for about 3 months now, when i got it it ran fine, but here lately i was fishing and i had the motor wide open and it began to bog down and now when i give it gas it goes dead and i can only idle with it, but i can tilt the motor out of the water and give it gas and it will do fine but when i tilt the motor back in the water it just goes dead when i give it gas. I can choke it when i give it gas and it runs maybe a couple of miles and hour faster but not much at all. any info would be helpful on whats wrong or what to do. thanks