MRO Magazine

Keeping the Flow Flowing

“You don’t know what you’ve got until it’s gone” is a phrase that is often used. This concept can be all-too-familiar for anyone who has ever neglected an engine-powered dewatering pump. A dependable pump...

September 1, 2013 | By By Pam Meyer

“You don’t know what you’ve got until it’s gone” is a phrase that is often used. This concept can be all-too-familiar for anyone who has ever neglected an engine-powered dewatering pump. A dependable pump isn’t truly appreciated when it’s working properly, but that dependability is really missed if a pump’s performance declines, or worse, the unit stops working altogether.

To avoid pump downtime and subsequent headaches, a preventive maintenance program for both the engine and the pump must be followed. It should include daily inspections as well as less-frequent checks.

Daily duties

Start each day with a pump inspection. Among the most important daily checks is the quality and level of the engine oil. Oil that’s contaminated can cause serious problems and decrease the life of an engine – likewise if there’s an insufficient amount of it. Change the oil or add more if necessary to reach the correct level, as per the manufacturer’s recommendation.


Check the gasoline level as well, making sure the tank is full, or at least full enough for the day’s usage. Also, look for any evidence of fuel or oil leaks. If a fluid is dripping, inspect the area for any parts that may need to be tightened or replaced.

Cleaning or possibly changing the air filter is another important practice that can prevent significant damage down the pipeline. A clogged, wet, dirty or damaged air filter can lead to a loss in power and shorten the life of an engine by allowing dirt or water into sensitive areas. A foam filter can be cleaned and reused, so it’s fine to check daily. A paper air filter, on the other hand, should always be replaced upon removal. It’s best to follow a recommended schedule to replace paper air filters in a timely fashion.

As well, inspect the condition of the hoses regularly. If they are worn, frayed or have any holes, the air gaps will likely cause the pump to lose suction. Patch any holes and seal leaking joints. A severely worn hose should be replaced. Finally, check the rest of the machine for broken bolts or nuts, or loose parts.

Of all the pre-operation checks, perhaps the most important thing to remember for daily maintenance is priming the pump before starting. Running a pump dry will damage the seals, causing a chain-reaction of further problems. If it’s a self-priming pump, simply add water. The term self-priming is somewhat of a misnomer, as water must be added to the pump each time it is used. The pump will then take over, build pressure within the volute and begin discharging.

Less-frequent checks

Once the pump has been prepped, it’s ready to go to work. In addition to daily checks, a pump requires other maintenance checks and services. While those don’t need to be done daily, they are crucial to the pump’s life and should be kept up with on a regular schedule. Generally, quality pump engines can operate up to 2,500 hours, and by following recommended maintenance schedules, you can only increase that time and the pump’s return on investment (ROI).

A few things need to be checked a couple of times a month, others even less frequently. For instance, a paper air
filter should be changed monthly. Although a foam filter can be cleaned and re-used, it’s still a good idea to change it monthly as well.

Dirty spark plugs can cause a decrease in power and poor starting performance, so the spark plugs should be checked semi-monthly for dirt, damage or excessive carbon build-up. Clean spark plugs with a wire brush or spark plug cleaner. Immediately replace any spark plugs that have cracked porcelain.

Additionally, it is important to clean and inspect the fuel strainer and fuel filter every month. Fuel can become contaminated during operation, and if it’s not removed, can lead to trouble with engine starts. Replacing the fuel line and carburetor is expensive, so it is essential to prevent unnecessary damage caused by contaminated fuel.

On an annual basis, give the pump a thorough inspection for dirty, broken or misaligned parts. Such parts can cause problems with the engine or pump components. Inspecting the entire machine gives the most comprehensive view of what needs to be cleaned and repaired.

Dusty conditions

It’s also worth noting that dusty conditions typically require the shortening of the length of time between regular services, as extreme dust can clog filter elements or contaminate fuel and oil. Depending on the pump’s environment, maintenance schedules may need to be adjusted to accommodate for less-than-optimal conditions.

Tips for troubleshooting

Even with a regular, proper preventive maintenance program, pumps may still experience problems. This is unfortunate, but common. Knowing what to look for and addressing it quickly will keep the problem from becoming a more expensive, time-intensive repair.

If a pump simply won’t run, the culprit is likely the impeller or engine. If the impeller is sticking, simply disassemble it, clean it and reinstall it. As for the engine, several different things could affect it and prevent if from starting.

The first thing to check is the spark plug. If it’s dirty, clean it. If it’s damaged, replace it. If it’s clean and damage-free, connect it to the plug cap and ground the plug against the engine body. Pull the starter to see if the spark is weak or nonexistent. If a new plug doesn’t spark, the ignition system is faulty and will need repairs.

The engine also might not start if the spark plug is loose or if the plug is wet with fuel. If the spark plug is wet, check to see that the fuel cock is closed. If so, close the choke lever and pull the starter handle a half-dozen times to see if the electrode becomes wet. If so, the problem may be that the fuel is stale, in which case it should be drained and refilled with fresh fuel. If the electrode is dry, the problem may be with the fuel intake of the carburetor. Try to see where the fuel stops in the engine.

A number of other things could cause a pump to not self-prime. Start by checking the air on the suction side of the pump; tighten the suction hose or pipe, if needed. Check the drain plug as well, to ensure that it has been tightened completely. Insufficient water inside the pump casing also will prevent the pump from priming.

Engine speed also can affect pumping volume. If the pumping volume has dropped, check the wear on the impeller, see if the suction hose may be too thin or too long, or retighten any loose parts on the suction chamber. This also might be caused by a high suction lift that would need to be lowered, water leaking from the water passage, a broken mechanical seal, or a drop in engine output or speed.

Adopting a proactive preventive approach ensures that crucial maintenance services won’t be neglected, preventing a domino-effect of problems as the pump goes down, time is lost and repair costs add up. It’s simple and straightforward; pump maintenance now will mean fewer issues later.

Following a good maintenance program, such as the steps detailed above, is among the best and most inexpensive ways to keep an engine-driven dewatering pump flowing.

Pam Meyer is the equipment sales manager for Subaru Industrial Power Products.


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