On my 2000 5.7 VP riser there is a hole in the side of the riser with a threaded fitting which has a check valve in it and a hose that goes to the spark arrester. One of the valves is bad which causes exhaust gas and some water to enter the spark arrestor. It appears that the way it is supposed to work is that it allows air to enter the riser, but not to come out towards the spark arrestor. The one thats bad allows exhaust gas and some water spray to enter the arrestor, which means I have a leaking riser I guess. Anyone know the purpose of this set up?
