Power Trowel Preservation

Proper maintenance is the key to longevity for any type of equipment — large or small. Without proper maintenance, not only will your equipment earn a quick trip to the scrap yard, but the performance of the machine and quality of your work will also suffer. One machine this especially holds true for is a walk-behind power trowel. From the first day a power trowel is put into service, it will be subjected to a harsh environment. If not properly maintained, this environment will take its toll on the trowel and its performance.

Daily Maintenance Checks

Let’s start with the basics. Prior to putting the machine on fresh concrete, always make a visual check of the unit. Starting with the engine, check the oil. Many engines now have low oil shut down switches built in so if the engine does get low on oil, engine damage will not occur. Nonetheless, it’s easier to add oil before rather than in the middle of a job. Check for oil leaks around the base of the engine and gearbox; oil dripping onto fresh concrete as you’re finishing is never a good thing.

Another way to check for oil leaks and spot early signs of trouble is to take a look on the floor where the trowel was sitting. Always check safety devices such as the belt guard being in place prior to operating the unit. The switch on the handle is probably the most important safety check since it will automatically shut the engine down if the trowel is let go.

Also be sure to check the operation of the throttle control and blade pitch control. Make sure all safety decals are in place, legible and replaced as needed. With liability what it is today, the importance of safety devices cannot be stressed enough. Remember, they are there to protect the operator.

Clean Up

A thorough cleaning of your walk-behind power trowel after each use is equally important. Sometimes this is difficult to do depending on the manpower available and the job conditions. Getting as much concrete off the unit before it dries is important in keeping the power trowel functioning properly. There are a number of ways you can do this, from scrapers to power washers to chemicals.

Chemicals are generally not recommended as they can cause other hazards and damage to the trowel if not properly used. But whatever method you choose, make sure you are always careful around the spider and arms of the walk-behind power trowel. A build up of concrete in this area can cause binding of the arms, which can affect the blade-tilting mechanism and performance of the machine. If you do use a high-pressure washer, use care: Some of them have such high pressure that they are capable of forcing water past seals and into areas that will cause problems down the road.

After clean up, it is recommended that you grease any grease zerks on the unit. This is once again particularly important in the area of the spider and arms. By greasing them after you use the machine, you will force out any water or build up of concrete, eliminating the potential for rust and corrosion.

Yearly Maintenance

As with any type of equipment, it’s always a good idea to give it a thorough check once a year. The best time to do this is during the off-season when things are a little slower. Start with engine maintenance. Most engine manufacturers recommend that the engine oil be changed anywhere from 25 to 100 hours — refer to your engine manual. At the same time, take a look at or change the spark plug, air filter and fuel filter. If there is no fuel filter, clean the fuel bowl. Refer to the engine manual for further recommendations.

Also, check the drive belt and replace it if it looks worn or cracked. Look at the clutch and make sure it is functioning properly and that it fully declutches. The oil in the trowel gearbox should be checked and probably changed depending on the hours you put on your trowel in a year. When changing the gear oil, be sure to put the recommended oil in as some gear oils contain additives that attack brass components.

All trowels have some form of lubrication on the trowel arms. Some are oil-filled, some have grease zerks and some have both. Whatever you have on your trowel, make sure it is serviced — this will ensure that the trowel arms move freely, which directly affects the finish of your work.

Essential Maintenance Tips

All of the above steps are important and will have a direct impact on the life of the machine, but won’t greatly affect the overall performance. The following steps below are where we get into the heart of walk-behind power trowel maintenance. These checks directly affect the performance of the trowel and the finish of the concrete.

Start by inspecting your blades. Whether you use finish or combination blades, make sure they are in good shape. If they are worn or bent, they can cause the machine to vibrate or wobble and leave a poor finish. If there is any question, they should be replaced. Finish blades can be reversed as long as they are in good shape on the backside.

Next, take a look at the blade arms. They should be checked for straightness. Some manufacturers have fixtures that can be purchased to check this. Now check the spiders where the trowel arms go in. If there is excessive play between the trowel arm and spider, replace the bushings in the spider. If your unit does not have bushings, it will be necessary to replace the complete spider. If this is the case, inspect the arms as they could also have wear on them. Generally on units with bushings you will not see any wear on the arms.

After you have checked to make sure the blades are good, all arms are straight and fit properly into the spider, there is only one thing left — to synchronize all the arms so the pressure plate tilts all of them the same. There are several styles out there, the most common being a rounded bolt head that contacts the pressure plate. For this style, it is important to make sure the bottom of the pressure plate is smooth and in good shape where these bolts ride. Whichever type you have, it is important they are all set the same.

Again, there are special tools that can be purchased from the respective manufactures that help you obtain the proper setup. The above steps can also be used as a troubleshooting guide any time you have a trowel that wobbles or vibrates.

A little bit of care and maintenance can go a long way to keep your power trowel operating properly for many years to come. More importantly, it will leave you with the professional looking finish you expect and deserve.

Gary Fieweger is a service manager at MBW Inc., Slinger, Wis.

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