1999 Volvo Penta "WT" Models Workshop Manual, Page 257Get this manual
Installation 1.lf installing new rubber bushings, apply 3M Scotch Grip Rubber Adhesive 1300 or 0II1C 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 pipePush pivot pin through bushings and valve until pin end is flush with outside of pipe
If 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 be adversely affected, and engine may suffer water damage