Service, explained
Yamaha water pump & thermostat service
- Every 300 hours or three years
- Impeller, housing, driveshaft & shift shaft seals
- Thermostats where fitted
Every 300 hours or three years, whichever lands first. Anyone can swap an impeller. The seals and the housing are what separate a water pump job from a water pump service, and on this coast they are the difference between a gear case that lasts and one that fills with water.
Why it comes due on the calendar here
Almost nobody on the Delmarva coast runs 300 hours in a season, so for most owners it is the three years that arrives first. It still counts. A rubber impeller takes a set sitting still, the vanes stiffen, and the first hot start of the spring is when a tired one gives up. Add what we run in: shallow bays, sand in suspension, and salt that never stops working. Sand is an abrasive going through a rubber pump, and it is the reason a pump here does not live the life it would in deep clean water.
What the job actually involves
The lower unit comes off. Once it is off, this is what we do, in this order.
- Water pump kit and impeller replaced. The whole kit, not a lone impeller — the wear plate, the gaskets and the seals come with it for a reason.
- The plastic housing replaced, every time. There is a metal cup inside that plastic housing. Over time the cup runs hot, and a hot cup can melt and distort the plastic around it. A distorted housing restricts water flow to the engine, which is an overheat waiting for a hot afternoon. We do not inspect it and hope. We replace it.
- Base plate off, driveshaft bearing carrier out, driveshaft seals replaced. Most shops do not do this. It takes longer and it costs a little more. Driveshaft seals are one of the two most common gear case leak points, and the unit is already apart — replacing them now is the cheapest they will ever be.
- Shift shaft seals replaced. The other common leak point. Same argument, same moment.
- Thermostats and thermostat gaskets replaced where the engine has them. A thermostat stuck part-open runs an engine cold and rich; stuck shut it does the opposite, and neither shows up on a gauge until it matters.
The part most quotes leave out
If you are comparing prices on a water pump between shops, ask the other one whether the driveshaft seals are in the number. Usually they are not. That is not dishonesty, it is a different job: pull the pump, fit an impeller, put it back. What you are buying when the seals go in is the next three years without water in the gear oil — because once water gets past a driveshaft seal it does not announce itself, it just quietly turns the gear oil milky and takes the bearings with it.
What it costs
We quote it the same day you ask. The number depends on your engine and on what dropping the lower unit turns up, and the service writer confirms it with you before any work begins. If we find something in there you should know about, you hear about it before we go further, not on the invoice.
Yamaha Marine Service Pro Elite dealer in Selbyville — five certified technicians, one of them a Master Tech. 💬 Ask the assistant or call (302) 436-1737.
The rest of the schedule
We are in Selbyville, Delaware, and we cover the Delmarva Peninsula — Ocean City and Ocean Pines in Maryland, Fenwick Island, Bethany Beach, Ocean View, Millsboro, Rehoboth and Lewes in Delaware. Keeping you on the water is the whole job.