When it comes to engine cooling, most modern combustion engines found on boats use a 50/50 mix of distilled fresh water and traditional antifreeze/coolant circulating inside the engine block because saltwater and freshwater are too corrosive. However, in place of using a traditional air-exposed radiator to lower the temperature of the coolant itself, the 50/50 engine mix is run through corrosion-resistant tubes inside a heat exchanger that saltwater/freshwater are pumped through. So, outside water is used to keep the engine cool – just not directly inside the block.
Here, we’ll focus on the boat impeller – essentially a gear-shaped propeller that does the pumping of the raw water from outside the boat through the dedicated plumbing channels in the exchanger.
Impellers are simple parts that typically provide a long service life. However, they do wear out and lose their ability to circulate water – resulting in overheating conditions which can cause significant engine damage.
Impeller pumps generally fail in one of two ways. The first is a gradual degradation in pump performance and flow as the impeller and housing wear over time. The second type of failure is sudden and catastrophic when the impeller wheel breaks apart, losing some or all its blades. This is frequently caused when the pump runs dry because a blockage has restricted water flow to the pump. Without that flow to cool the impeller pump, it soon overheats to the point of disaster.
In most cases, you can tell if an impeller is worn simply by checking a specially designed wear ring or wear plate, which are seals between the impeller and its casing. When the impeller starts to become worn, the seals are designed to sacrifice themselves and leak – serving as an early warning that the impeller itself must be replaced. Wear rings are typically found on pumps with closed impellers, while some pumps with a semi-open impeller may feature a wear plate instead. Inspect for signs of leakage around the pump housing – if you see leakage there, it’s time for replacement.
Many boating experts recommend replacing the impeller once a year no matter what, as a notable amount of wear can still occur, but not be enough to cause the telltale leak. For example, boats that sit unused for a period of time tend to see problems when the pump is started if the impeller should bond itself to the housing over time (it happens). Impellers can also wear more than you realize when plant growth, plastic bags, or other gunk reduce flow through the water inlet tube, or if a seacock valve is left closed after the engine is started.
BOATiD offers a great selection of pump repair kits which include a new impeller, wear ring or plate, gaskets, hardware, and more. With all new components, we recommend impeller wheel repair kits because they represent a great value that’s a smart money purchase for any boat owner.
Installing a new impeller is a quick and easy job that can be done by anyone with basic mechanical skills. If you should find the old impeller wheel has broken apart, it’s best to flush the entire system to ensure any and all pieces that might cause further blockages or damage to the new impeller pump are removed. For this, we recommend the Camco DIY Marine Winterizer. And if you’d also like to use the winterizer to flush out the coolant within your engine block as well, we’ve got a good selection of engine coolant types to choose from.
Along the left side of your screen, you’ll see check boxes that allow you to narrow your search when it comes to materials the impeller wheels are made of, drive types (the style of center the impeller accommodates), number of blades, outer diameter, shaft diameter they’re designed for, and more.
BoatiD.com carries many popular sizes and brands of boat impellers from proven manufacturers such as Reverso Pumps, Seachoice, Johnson Pump, Raritan, Jabsco, Albin Pump Marine, Sierra, Sherwood Pumps, WSM, and Shurflo.
In addition to impeller wheels and kits, you’ll also find individual components such as gaskets, pump housings, pump bearings, insert cups, sealing rings, and more on our website. Plus other things you want and need such as electronics and navigation equipment, replacement parts and hardware, plumbing-related items, maintenance, and upgrades to make the boating experience more enjoyable.
Whatever you’re looking for, we’re confident you’ll find the right products on the digital shelves of our online store. Visit us at BoatiD.com for all your marine needs, or contact our knowledgeable specialists at 888-453-5144.