Blown fuses on macerator pumps

[Pacificcoast101]

Last week we began having problems with the macerator pump in our starboard fish box. Each time I would turn it on, it would blow the 20 amp fuse. I can't get my arm nor any wrench to remove the pump and there is only an inch or so above the top of the pump, so I can't turn the impellor with a screwdriver. I was going to just replace the pump by removing the hoses and putting a new one where I could reach it. Today our macerator from the head blew a fuse. I replaced the fuse and it blew again. I can reach this one under the sink, but turning with a screwdriver didn't stop the fuse from blowing. Any suggestions before I spend money I don't have on an electrician?