I just posted and tried the info given.. Have a Mercruise 5.7 L engine..
The exhaust flaps on one side were burnt off. I know there is a jam on the
one side because all of the water comes out on the other side, plus i can
spray water up from the out drive on the one side but not the other. Here
is what i have tried to free the debris 1) spray water down the exhaust pipe
on both sides 2) spray water up the pipe from under the out drive 3) tried a
pressure washer also. My hand only goes down to where the pipe bends and
connects from the other side....

Suggestions please...

THANKS! ! !