My boat whines in reverse
QI’ve had my boat a year and there is a whining noise when reverse is engaged on the Lister LH150 gearbox. I have checked the oil levels and it all seems clean and viscous. The box is quiet in forward and neutral.
One thing confuses me: the Lister handbook states: “The external ends of the reverse gear operating shaft must be oiled frequently to prevent rust formation that may stiffen the shaft. To lubricate the port side of the shaft, the locating screw should be removed and a few drops of oil pored down the hole.”
AIs it definitely the LH150 (pictured), not the mechanical L100? If you have a single lever control, it’s definitely an LH150 but the bit about the reverse gear operating shaft seems to be for an L100 mechanical box with a great big lever through the floor.
Are you sure it isn’t just normal noise? The LH150 uses a sun gear and planet gears in a drum to provide reverse gear, and it’s a lot of moving and meshing gears, which will create a noise like you describe. The bearings might be worn, but it all sounds normal to me. Just make sure that you are using SAE80 gear oil in the gear and reduction box, not engine oil or AFT. An LH150 implies a older boat, so consider the cost / benefit of stripping the box just to see if there are worn gears or bearings: even it there is wear, reverse gear is not usually used for long at any one time.