Key points for purchasing second-hand power trowel and common methods to avoid pitfalls

Selecting a second-hand polishing machine is a job that requires a lot of experience and skills. It can help you obtain a practical device at a lower cost, but if you make a wrong judgment, the subsequent maintenance and delayed construction period may cause you to lose more than you gain.

The following is a detailed list of key points for choosing a second-hand polishing machine and common methods to avoid pitfalls. We hope it can be of great help to you.

Part One: Key Points for Selection (Observation, Auscultation and olfaction, Inquiry, and Palpation)

Ⅰ. Inspection - Check the appearance and core components

Fuselage structure

Chassis (grinding disc) : This is the most crucial part. Check if it is flat and free of deformation. Slight wear and tear is normal, but if the wear is severe, there are pits or obvious deformation, it will lead to poor polishing effect and higher replacement cost.
Blade (scraper) : Check if there is still sufficient thickness. If the metal substrate has been worn out, it needs to be replaced immediately, and this cost should be included in the cost.
Protective cover: Check for any damage or severe deformation, as this is related to operational safety.
Overall framework: Check for any signs of welding, cracks or repairs, which could be a sign of severe impact or drop.
Engine (heart)

Brand: Give priority to well-known brands such as Honda, Kohler, Briggs & Stratton, etc. Spare parts are easy to find and maintenance is convenient.
Appearance: Check for any cracks in the engine casing, especially in the base and radiator sections. Check for obvious oil stains or carbon deposits. This might be a sign of oil leakage or poor maintenance.
Air filter: You can ask to remove the air filter to have a look. If the inside is very dirty or even soaked with oil, it indicates that the previous owner might not have paid much attention to maintenance.
Engine oil: You can pull out the oil dipstick to check. If the engine oil is black, viscous or contains metal debris, it indicates that the engine wear may be relatively severe and the maintenance condition is poor.
Transmission system

Gearbox: Check if there are any signs of oil leakage on the gearbox housing. Rotate the drive shaft by hand to feel if it is smooth, and if there is any jamming or abnormal noise.
Belt/chain: Open the protective cover and check if the belt has cracks, wear or looseness. Check if the chain is loose and free of oil and rust.

Ⅱ. Listen (Smell) - Test the operating status

Be sure to ask the seller to start the machine for testing!
Startup performance

Cold start is the most illustrative. Observe whether the rope pulling is smooth and whether the machine can start smoothly within one to three rope pulls. If it is difficult to start, there may be problems (such as carburetors, spark plugs, insufficient compression, etc.).
Engine sound

After starting, listen to the sounds of the engine idling and accelerating. The operation should be smooth. A regular "tap-tap" sound is normal (valve sound). If there are loud "clicking" sounds, knocking sounds or irregular noises, it indicates that there is severe wear inside.
Transmission system sound

Let the trowel run idle and listen for any abnormal "clattering" sounds from the gearbox and transmission parts. The voice should be even and deep.
Vibration condition

When the machine is running, it should be smooth and the vibration should be within a reasonable range. If the vibration is abnormally severe, it may be due to deformation of the chassis, unbalanced installation of the blades or problems with the engine base

Ⅲ. Ask (Communicate) - Understand History and Background

Purchase time and source: Inquire about the specific year and channel of purchase of the machine to determine its service life.
Usage frequency and scenarios: Is it for occasional household use or long-term high-intensity use by professional teams? The latter naturally wears out more severely.
Maintenance and repair history: This is of Paramount importance.
Has there been any major overhaul? (Such as engine cylinder opening, gearbox replacement
When was the last time the engine oil, air filter and spark plugs were changed?
Have there been any accidents (such as tipping over or collision)?
A reliable seller will tell the truth, while a evasive one needs to be on guard.

Ⅳ. Cutting (Practical Operation) - Load Testing (If conditions Permit

If possible, conduct a brief load test (such as grinding it on the ground). Observe after the load is applied:
Whether the engine is prone to stall and whether the power is sufficient.
Check for any slippage or abnormal noise in the transmission system.
Whether the machine moves smoothly and if it deviates.

Part Two: Common Traps and Avoidance Methods

Trap One: Refurbished machines and beauty machines

Trap description: Merchants thoroughly clean and paint the machines to make their appearance look as good as new, thereby covering up internal wear and tear and malfunctions.
Avoidance methods

Pay special attention to the screws and interfaces: It is very difficult for a refurbished machine to have no signs of any screws being turned. Check whether there are any signs of wear on the engine fixing screws, chassis screws, etc.
Paint surface consistency: The original factory paint surface is usually uniform. If you find that the paint color of some parts does not match the overall color or the paint layer is too thick, it might be due to later spraying.
Don't judge a machine by its appearance: Don't be deceived by a clean exterior. The key is to check its operating status and internal wear.

Trap Two: Accident Repair machine

Trap description: The machine was once sold after its chassis and frame were deformed due to a fall or collision. It was sold after simple repairs.
Avoidance methods

Check the flatness: Place the machine on a flat ground and observe from the side whether the chassis is fully in contact with the ground and if there is any warping.
Check the welding points: Carefully inspect each connection point of the rack to see if there are any irregular or rough welding points in the later stage.
Running test: During no-load operation, observe whether the machine is stable and if there is any regular swinging. This might be a sign of an uneven chassis.

Trap Three: Assembling machines

Trap description: Piecing together a complete machine with "good" parts from different scrapped machines, which has poor compatibility and stability.
Avoidance methods

Brand consistency: Check whether the brand, model and newness of the main components such as the engine and fuselage match. Assembly machines often give the impression of being "mismatched".
Check the nameplate: Whether the information on the body nameplate (such as model and production date) is consistent with the seller's description.
Poor comprehensive operation: When the assembly machine is in operation, various minor problems may occur frequently, making it feel "not smooth".

Trap Four: Hidden Disease Mechanism (The most Concealed Trap)

Trap description: The machine performs okay when it is cold or unloaded, but once it is heated up or loaded, problems become apparent (such as insufficient power, severe abnormal noises, and engine stalling).
Avoidance methods

Persist in long-term testing: Let the machine run for 10 to 15 minutes and observe whether the state is stable after warming up.
Load testing is required: This is the best way to verify the true state of the machine.
Check the engine oil: After warming up the machine, stop it immediately and check the engine oil. If there are many small bubbles (emulsions) in the engine oil, it might be that the cylinder gasket is being washed away, which is a big problem.

Summary: Decision-making List for Purchasing a second-hand polishing Machine

Before deciding to purchase, quickly check the following list:

Inspection items	Qualification standard	Be cautious/give up
Fuselage chassis	Smooth, evenly worn, and without deformation	Deformation, cracks, wear limit
Engine	Well-known brand, smooth start-up, stable operation, pure sound, no oil leakage	Difficult to start, severe abnormal noise, oil leakage, and heavy smoke
Transmission system	The rotation is smooth without any abnormal noise, and the belt/chain is not aged	There is abnormal noise, jamming and oil leakage
Seller Description	Be honest, answer all questions, and keep clear maintenance records	Vague and evasive, concealing history
Price	In line with market conditions (approximately 30% to 50% of a new model)	Far below the market price (" There's no such thing as a free lunch ")
Test run situation	The hot and cold units start well and operate stably under no-load or load conditions	Any test is unqualified

Final suggestion:

If possible, bring along an experienced master craftsman or mechanic. Their experience can help you discover many problems that beginners fail to notice. When making a purchase, it is best to sign a simple written agreement with the seller, clearly stating the condition of the machine, and keep the payment voucher for unexpected needs.
Remember, the primary principle when purchasing second-hand equipment is "It's better to miss out than to buy wrongly." Wish you could find a sturdy and durable good machine!
 

Note: The parameters provided in this document are for reference only and are not mandatory. Due to differences in technical characteristics between different brands and models of laser levelers, please consult the manufacturer for a suitable solution before actual operation. This reference document assumes no responsibility for any issues arising from failure to follow the manufacturer's instructions.

Thanks to all the friends who support and trust Shandong Vanse Machinery Technology Co., Ltd.

If you want to know more about Shandong Vanse Machinery Technology Co., Ltd. or have any questions, please feel free to contact us:
• Tel: +86-13639422395
• Email: sales@vanse.cc
• Website: www.vansemac.com