I have a manual pump head that I installed about 2 seasons ago. The pump on it is starting to stick a lot. Especially now that she just went back in the water after sitting all winter. Can I use lock carbon on it or WD40? Is there a special lube for it.
If it’s the ubiquitous Jabsco, there is a large nut that forms the seal holder in top of the pump. Using an adjustable spanner (wrench in USA ) pull the pump handle to the top, undo the nut, tip the shaft to the side to vent the pump (stops water spilling into the boat) and remove the plunger. A small amount of waterproof grease on your finger, wipe it onto the inside of the pump cylinder and reassemble.
Takes five minutes, will stop the sticking for a few months. There will be some who say “oh yes, but the grease will damage the seal”. Yes it will over several years. When it does, a dollar will buy a new o-ring that will last the next five years. Insert it next time you fix the sticky. 😊