I bought a new Johnson pump kit off the internet as a replacement some time ago thinking it has a shortened life with how much use it gets. After really looking at the switch and associated wiring I decided to replace the whole unit. I made a new housing for the switch which has a "hood" to keep off localized dripping water and put a gasket behind the plate to help keep water out. Looking at the manual I noticed that they show a pre filter that could be mounted in line. I also noted that there is no valve between the wash down pump and the raw water filter. These means that if the pump failed and leaked, bad news. ( I finally have a reason to keep the raw water valve closed.) I will be installing another in line valve before the wash down pump just in case. The manual suggests replacing the lower end of the pump with the pressure valve if it fails to come back on. You might consider contacting Johnson pump, they might have a secret fix. You might consider trying to blow pressured water through it to see if that changes things. As work on the Tug goes, it was an easy fix with good access.