Mercury/Mariner Outboard Water Pump Impellers Repair Kits

Impellers pump cold water into your boat's engine to cool it down while in use. If you have a bad impeller, it can cause big problems. Impellers are critical to engine cooling systems, so take along a spare.

Mercury outboard engines rely on the water pump for cooling. The impeller is the heart of the water pump; inspection and replacement is required on a regular basis to keep the engine running at optimum temperature. Force Mercury recommends changing the impeller every 300 hours... it's in the owner's manual. It's an easy enough job to do yourself if you have some mechanical skills. Signs of a bad boat impeller are either boat engine overheats when you try to accelerate, loss in impeller vanes flexibility, physical wear & tear like cracks in impeller vane roots, and melted or worn-off vanes. Even if you see less or no water coming out of the tell-tale, it might be due to a bad impeller. Impeller pumps generally fail in one of two ways. This is usually caused by running the impeller pump dry. Remember, the fluid being pumped provides the cooling and lubrication for the pump. This is often caused by a water inlet seacock not being opened or a plastic bag covering the water inlet. Your boat's impeller is a series of rubber vanes molded around a hub. The tips of these flexible vanes can wear out for many reasons due to simple use or if the boat is in sandy water. Impellers can also wear out by becoming stiff and brittle due to the motor sitting unused for several seasons or being exposed to heat. These flexible vane tips wear out for several reasons, none of which can be prevented. Most marine engines will have a raw water pump with a flexible impeller. It is used to pump raw water from outside the boat through the engine's raw water cooling plumbing. These impellers are very reliable but some care is required. They should never be run dry. Mercury and Mariner are the same company, both owned by the Brunswick Corp. Mariner was originally an Australian-licensed company that re-badged overseas engines and sold them locally under the 'Mariner' brand name, mostly US-made Mercurys and a few Johnsons. At present, Mercury product brands include Mercury, Mercury Racing, MerCruiser, and Mariner outboards (sold outside the U.S.). In 1999, the decision was reached to end Mariner sales in the U.S. but to continue distribution internationally in markets where it remains popular. In the U.S., loyal Mariner owners were downhearted. The only difference between Mercury and Mariner is that one is grey and no longer made and one is black. You can swap parts between the two. The force was purchased by Mercury from Chrysler and is no longer manufactured. Introduced in Australia in 1974 and two years later in the U.S. and Europe, Mariner instantly doubled the distribution potential for Mercury Marine. The new outboard brand established a foothold in Europe, thanks in part to a decision by OMC to sell direct to dealers, eliminating the loyal, long-term distributors. Mariner was originally built under a joint venture with Yamaha, which was ended by the Federal Trade Commission’s ruling that the agreement hindered competition. By the early ’80s, Mariner and Mercury were becoming more similar than different. When electronic fuel injection was introduced in 1986, the transition was complete; the two outboards were mechanically the same. In 1999, the decision was reached to end Mariner sales in the U.S. but to continue distribution internationally in markets where it remains popular. In the U.S., loyal Mariner owners were downhearted. Even though Mercury and Mariner had been the same product — except for paint and decals — for more than a decade, the faithful never accepted the reality, expressing a wish for the return of Mariner in the U.S.

Mercury/Mariner Outboard Water Pump Impellers Repair Kits are critical to keeping the engine cooling systems running smoothly, so keep an Impellers Repair Kit handy. Mercury/Mariner outboard engines rely on the water pump for cooling. The Mercury/Mariner impeller is the heart of the water pump.