exhaust hose/cupling

[Alfred jobs]

this is a 1991 omc cobra 3.0 4 cyl. I saw the paint was pelling on the exhast pipe under the riser so i took the riser off and the flapper was gone i ran a camera threw (all clear) then i put the rubber hose on the riser when i looked at it well you all know how the exhaust inside flares out and has notches in it this is against the rubber and the notches are so small you can not fit a half a pensil threw them and theres only 6 of these notches the riser is clean and i wire brushed the flared end and made no change my dealer got me 3 difrent hoses 1 volvo 2 omc and they all did the same thing .My idea is to lightly gring about 1/16th of an inch around the flare and the same for the notches what do you think ?