i installed 2 new speakers in the rear the same kind that was instaled in the front from futureshop and only 1 side works and somtimes it cuts out at random(i just tied the power wire onto it) would my decks fuse be why its not getting enough power because one time (the second day i was playing it my deck shut off and the fuse blew) and the speedometer stopped working (fuse) would putting a larger fuse in it make all the speakers work?? btw i have these speakers

http://www.futureshop.ca/catalog/proddetail.asp?logon=&langid=EN&sku_id=0665000FS10 085400&catid=

so you see its 75watts rms when i turn on my deck does it it turn on 75wats x4?? or no?