1999 Volvo Penta "WT" Models Workshop Manual, Page 292Get this manual
Installation 1If installing new rubber bushings, apply 3MScotch Grip Rubber Adhesive 1300 or OIVC Scotch Grip Rubber Adhesive 1300 to outside of tips, and insert into inside of exhaust pipe
2Position valve with longest lip pointing down, and insert into pipePusn pivot pin through bushings and valve until pin end is flush with outside of pipeIf valve is not positioned properly (long lip down), it will restrict exhaust flow and fail to prevent water backing up into engineValve must also move freely and not bindBoat performance would adversely be affected, and engine may suffer water damage