Test Tanks for Outboard Engines

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Anyone who has ever owned a boat powered by an outboard motor knows not to start and run the engine when it is out of the water. The outboard motor uses water for cooling and when run dry a variety of bad things will quickly happen and vital components, such as the water pump impeller, will fail.

Ear Muffs

There are several ways to run your outboard motor when it is out of the water, even if it’s still mounted on your boat. For boat owners who keep their vessels on a trailer and parked in their back yard there are several options for running your engine without having to make a drive to the lake. An inexpensive and easy-to-store device is called an ear muff, simply two round, rubber cups that clip onto each side of the lower unit over the water intake vents. Attached to a garden hose, water is pumped to the ear muffs and the engine can be safely started and run. Make sure to park your boat where drainage will occur as water will pour onto the ground.

Fifty Gallon Barrel

In the old days boat owners simply lowered their outboard engines into a fifty gallon drum filled with water to test the motor. This was a convenient method as the outboard could remain attached to the transom of the boat. But running the motor in such a small container of water meant you could only run it at slow speeds, as throttling up would cause vast amounts of the barrel water to splash out, placing the lower unit at risk of running dry.

Custom Test Tanks

It wasn’t long before both boat owners and manufacturing companies realized the need for a test tank that was large enough so the outboard could be tested in gear and at higher throttle. Many companies began custom building test tanks that were long enough to prevent the prop wash from spilling from the tank, making troubleshooting on dry land much easier for the mechanic.

Hydraulic Test Tank

For outboard mechanics who have the need to test run outboards inside their shop with the motor off the boat, a test tank with a hydraulic transom lift meets the needs for large and heady engines. Once the outboard is lifted off the transom it is hydraulically lifted, rotated over the tank then lowered into the water. This type of large tank is also good for testing under load with the propeller turning. (

Flush Bag

Sailboat owners who use a small outboard motor when not under sail find the flush bag a handy piece of equipment. After motoring out of port, many sailors choose to immediately flush the salt water out of the outboard to prevent corrosion. The light weight flush bag is pulled up around the motor and filled with fresh water, and the outboard is run for a few minutes to clean the unit. (