Check out the wiper motors that are installed on your boat and if they are made by Marinco, buy replacement parfts that are Marinco. Buy the parts for the unit that is stalled on your boat. Briggs and Stratton parts will not fit on a Chevy.
If you have problems with customer service at West Marine - talk to the store manager, the district manager, the area vice president, and call, email, or write to Geoff Eisenberg CEO at WM. Goeff will make some changes at that store.
It is WM policy to greet all customers when they come in the front door, ask them if they need help, acknowledge them everytime you come within 10 feet of them, when they ask for something you take them to the item and answer all questions about the item. When they leave you thank them for shopping at WM. At least that is the way customers are treated in our part of Florida. Most of the WM stores here are staffed by people with30 to 60 years of boating experience
If you need help with your wiper blades, bring you boat, car, or truck to Florida and I will install them for you at WM.