Video series on how to buy and sell lawn mowers. This series give you insight on how to purchase lawn mowers, repair, and then sell for a profit. This is a great way to make money on the side or learn the value of money while maintaining a budget. Both of the mowers shown in the video were being thrown away, therefore I got them for free. The repair videos will include how to replace a mower blade, sharpen a mower blade, change the oil, clean the carburetor, change the wheel bearings, testing spark, and testing compression.
Step 1: How to Clean a Carburetor
Cleaning the carburetor is basically a must when acquiring a lawn mower. Lawn mowers are exposed to a large amount o debris when cutting the grass and if fuel has sat in them for extreme periods of time, both will cause operation issues with the engine. This can include hard starts, erratic idling, no start, poor performance, and poor fuel consumption.
- fuel line
- hose cutter
- ratchet and socket set
- safety glasses
- rubber gloves
- carburetor cleaner
- replacement gaskets
- new air filter
Start by removing the air filter cover which is held on with a bolt on the top side. Remove this bolt and then unclip the cover on the bottom side. Remove the air filter and then 3 bolts behind the air filter. Finally remove this plastic cap which covers the carburetor, there will be a hose in behind that connects to this plastic case. Disconnect the fuel lines by removing the pinch clamps first using plies. Use the pliers to gently twist the lines as they can stick when they haven’t been removed for a longer period of time. Remove the two bolts holding the carburetor to the block. These can be a little harder to gain access to due to the tighter space so take your time not to strip the heads. Keep a rag or container handy in case some fuel spills out, you can also pinch the line using locking pliers or a clamp or use something to plug the fuel line such as a bolt. Remove the fuel line, then pull the carburetor back from the engine block. Disconnect the throttle control linkage, finally the carburetor is removed and we can begin disassembly for cleaning now. There might be fuel still inside so again have a rag or container handy. Remove the float bowl bolt and the plastic float bowl is removed by taking out the pin. Above the float bowl is the needle. This particular model of carburetor does not have a high and low speed jet as they are fixed settings from factory, therefore if the carburetor is too far damaged, a new unit will need to be purchased. Using a carburetor specific cleaner, clean the unit. Clean the carburetor in a pan to prevent any overspray on other objects and use a soft wire or fishing line to help clean out any of those orifices. Clean the float and float bowl and then clean the passage in the float bowl nut. Allow the cleaner to evaporate and then reassemble. Reassembly is in reverse of disassembly, inspect any gaskets and replace accordingly. For the fuel line replacement, if your tank is full, you will need to empty the fuel. As you can see this line is deteriorated and if it was leaking now, will be leaking very soon eventually. Use a fuel compatible hose only as this will withstand the damage caused by fuel . The new hose should fit tightly around the fitting and ensure the clamp will also keep pressure on the hose connection. Match the length and cut the new hose accordingly. Side cutters can be used, but I am using a specific hose cutter instead which allows for a clean and straight cut. Transfer the old hose clamps to the new hose, install the new fuel line. Finally install the carburetor in reverse of removal.
Step 2: How to Replace a Mower Blade
Sometimes a mower blade replacement is required if the lawn mower didn't come with a blade or it's too far worn. A lawn mower equipped with a new blade is an excellent selling feature as the new owner has one less maintenance item to worry about. Blades can also be sharpened, a tutorial for that will be included further on in the series.
- ratchet and socket
- block of wood
- new replacement blade
- wire brush
- medium grade thread locker
- torque wrench
- axle stands
Remove the spark plug wire and tuck it off to the side, this will prevent the lawn mower from starting which could harm you. If your lawn mower is equipped with electric start, then also disconnect the battery. Tilt the lawn up on the air filter carburetor side. I am using jack stands to keep the lawn mower safely elevated. I would highly recommend wearing gloves to keep your hands safe. Wrap a cloth or rag around the one side of the blade so you have an area you can hold it into place. Use the appropriate size socket to loosen and remove the center bolt. If you find you’re having trouble loosening the bolt, you can also use the assistance of a block of wood to jam the blade into place. When picking a new blade, ensure it is the correct length, will fit your model of mower, and meets your cutting needs. Finally the old blade can be removed, this does have a removable flange which sits on a keyed shaft. It’s good practice to remove this and clean up the flange with a wire brush to remove any baked on dirt or rust which may cause problems when bolting down the new blade. Ensure the bolt hole in the center of the blade is the correct size, then ensure the two locking pins are also in the correct location as some model blades do not have slotted holes. Finally clean up the bolt with a wire brush. Apply a thread locker to this bolt as it will prevent it from loosening and also resist the threads from corroding, only use a medium grade thread locker. Install the blade and ensure it is in the correct orientation, sometimes they will have the orientation stamped on the blade, either saying this side up or down. Another way to tell if the slant portion, also known as a wing tip should face up, therefore the bottom on the blade should be the smoothest part, then the cutting edge faces the direction of travel. If you wish to use a torque wrench, the torque valves for a walk behind mower’s blade is normally between 35 to 60 foot pounds, but this will vary between models so be sure to consult with your owners manual.
Step 3: How to Change the Oil
Another maintenance item that a new owner doesn't have to worry about is changing the engine's oil. Mowers will have specific intervals for this which can vary between manufacturers. Unfortunately most lawn mower owners don't change the oil so it's often an overlooked area.
- 3/8” drive ratchet
- 6” 3/8” drive extension
- clean rag
- new oil
- drain pan
- pick or wire brush
Start by warming up the engine, this will reduce the viscosity of the oil, allowing it to run out of the engine much easier than compared to when it’s cold. Remove the spark plug wire and tuck it off to the side. If your lawn mower is equipped with electric start, then also disconnect the battery. Depending on the oil plug location will affect how we raise the mower. For this model the plug is located in the center, therefore to drain the oil it will need to be fairly level while maintaining room for the oil drain pan. Tilt the lawn up on the air filter carburetor side, if this side were to face down, the oil would drain into the carburetor causing issues. The one side will be sitting on concrete block and the oil side I will be using jack stands which can be adjusted. Locate the oil plug which will be in the crank case casting, sometimes these can be filled up with debris so use a wire brush or pick to clean the area and whole. Wipe off the area with a rag to ensure so contamination when we reinstall the plug. Using a 3/8” drive ratchet and 6” extension, insert the extension’s end in the square slot and remove. Oil may or may not come out immediately, so have the oil drain pan ready. Set the mower level with the drain pan underneath and allow the oil the drain. Allow the oil to drain completely and you may need to loosen the oil fill cap slightly to allow air in. Once done, ensure the area is clean and reinstall the oil plug. Tighten the plug, torque valves do vary so consult with your owner’s manual. Now place the lawn mower back on the ground safely. Locate the oil fill location, wipe off the surrounding area to remove any dirt, then remove the oil cap. Fill the engine with the required oil, requirements will vary depending on engine models and the weight can also vary depending on your climate. Fill with the correct amount of oil, check the dip stick to determine it’s level and ensure the level reads between the minimum and maximum lines. Check for any leaks and you’re done.
Step 4: How to Clean a Tecumseh Carburetor
Another style of carburetor to help assist with cleaning procedures. A dirty or clogged carburetor can cause no start or starting issues, reduced power, reduced efficiency, and erratic idling. Carburetor styles will vary between engines, but the same basic procedure applies.
- carburetor cleaner
- drain pan
- ratchet and socket set
- safety glasses
- interlocking pliers
- fishing line, torch cleaning tips, fine wire
Remove the two retaining bolts on the engine cover and remove the muffler as this also limited space for the other intake manifold bolt. If you find the bolts are binding up when being removed, try to apply some penetrating oil or keeping tightening and loosening them to prevent damage on the threads. Now we can finally remove the intake manifold. Starting with the bottom fastener which can only be accessed by a wrench. Then the other fastener slightly hidden behind the engine cover. Sometimes this assembly can stick to the gasket surface from sitting so slightly pressure maybe need to break it free. You’ll have a throttle spring to remove, along with the throttle control linkage. Remember which hole the throttle linkage connects to and then remove the fuel link clamp with plier, then twist and remove the fuel link. Keep in mind fuel might be present in the link so have a rag or container handy. Plug the line using a bolt, then facing the link upwards. Finally the carburetor is removed. Considering the outside of the carburetor is fairly dirty, using a tooth brush and carburetor specific cleaner to remove the dirt. There might be fuel still inside so again have a rag or container handy. Remove the float bowl bolt. The float is removed by taking out the pin, it’s good to shake the float bowl and listen for any liquid as sometimes these can leak causing running issues. Above the float bowl is the needle, this particular model of carburetor does not have a high and low speed jet as they are fixed settings from factory, therefore if the carburetor is too far damaged, a new unit will need to be purchased. Using a carburetor specific cleaner, clean the unit. Use a soft wire or fishing line to help clean out any of those orifices. Torch cleaning tips can also be used, but you must be extremely careful not to file away any material which will affect the design of the carburetor. Clean the float and float bowl and then clean the passage in the float bowl nut. Allow the cleaner to evaporate and then reassemble. Reassembly is in reverse of disassembly and inspect any gaskets and replace accordingly. Inspect the fuel line for any damage and replace accordingly. Finally install the carburetor in reverse of removal.
Step 5: How to Sharpen a Blade
The three signs of when you have a dull blade is when the freshly cut grass will not have a clean cut. The blades of grass will have a torn appearance. You will also find when you make a pass in cutting the grass, there will be high spots left behind. And finally upon visual inspection of the blade, the cutting edge will be dull or chipped. A lawn mower blade should be sharpened about every 20hrs of usage. This will vary sightly depending on what type of grass is being cut, height, and contact with dirt. The blade should be replaced if the chipped are too deep, has already been sharpened several times, is rusty, too thin, or is bent.
- socket and ratchet
- wire brush
- thread locker
- axle/jack stand
Remove the spark plug wire and tuck it off to the side, if your lawn mower is equipped with electric start, then also disconnect the battery. Tilt the lawn up on the air filter carburetor side, here I am using jack stands to keep the lawn mower safely elevated. I would highly recommend wearing gloves to keep your hands safe. Wrap a cloth or rag around the one side of the blade so you have an area you can hold it into place and using a block of wood to jam the blade in place just to give you a bit of variety on techniques. Use the appropriate size socket to loosen and remove the center bolt. Finally the old blade can be removed and now is a great time to clean any suck on grass underneath the deck if needed. It’s good practice to clean up the flange with a wire brush to remove any baked on dirt or rust which may cause problems when bolting down the new blade. We’ll also clean up the threads on the bolt too. For sharpening the blade, I’ll be using the least costly method which is a file. It’s best to clamp the blade somewhere so you can have a secure surface to work on. Using a flat metal file begin to sharpen the blade. Push into the sharpened edge, pulling material away, matching the existing angle. Normally you can start with the rough cut on the file first, this will take material away quicker removing any edge damage. I would highly recommend keeping your gloves on just in case you slip, you at least have some protection from the sharp edge. Once you’re getting close to a final edge, then switch the file over to the finer cut side, giving you a smooth finished edge. You may need to clean up any material which has slightly pushed over on the other side if the blade has hit a harder object such as a stone. Finally we now need to balance the blade, which is needed to prevent any vibrations which can become a safety concern or cause premature failure on the mower. Take a wire brush and clean any rust or stuck on dirt. I’m using a bolt inserted in the lawn mower handle bars and will be preforming a vertical balance check. Watch for which side falls, the side that falls is heavy, therefore material needs to be removed from here. Continue to file the sharp edge of the blade to remove some material and check again. Once done, the blade should sit level. Apply thread locker to this bolt as it will prevent it from loosening and also resist the threads from corroding. Install the blade and ensure it is in the correct orientation. A block of wood can be used to jam the blade if needed. If you wish to use a torque wrench, the torque valves for a walk behind mower’s blade is normally between 35 to 60 foot pounds, but this will vary between models so be sure to consult with your owners manual.
Step 6: How to Replace Wheel Bearings
While this wasn’t a common option, some lawnmowers were equipped with bearings in the wheels. They’re fairly easy to replace or you can opt out for the regular wheels which I what I’ll be doing. The reason I’m not buying new bearings is that I’d like to sell this before the snow comes around and the cheapest place I did source out bearings takes about a month for them to arrive. I’ll give a little more info on the bearings in a moment.
- new bearings or new wheels
- standard/flat screwdriver
- round punch
- socket and ratchet
- axle stand
Remove the center cap using a standard screwdriver, they just simply snap into place. Once the cap has been removed, loosen the center nut using the correct socket and a ratchet. Elevate the mower and I would recommend removing the spark plug wire just to be safe and prevent the mower from starting. To buy new bearings locally from a small engine dealer or Sears as this is a Craftsman, they want about $30 per wheel, but this varies between sizes. New bearings can be purchased online, I found sources on Amazon and Ebay which is only $10 for a full set which is 8 bearings in total. You will need to measure the shaft diameter it fits on, along with the outside diameter of the existing bearing where it sits inside the wheel. Remove the nuts to completely remove the wheels, pull the wheel off the shaft. There are two bearings on each wheels, an inner and outer bearing. Place the wheel on two blocks of wood, but allow the center to be unsupported so the bearing will pop out. First using a punch, it must be small enough to fit in the center of the bearing, place it on the backside of the other bearing and then continue to tap it out with a hammer. Continue to work it around in a circular motion so the bearing doesn’t become wedged in the wheel. Finish up with the other bearing using the punch. Using a standard screwdriver, the outer case of the bearing may have an edge where you can you fit in a screwdriver to remove it from it’s location. Carefully pry out the bearing and do not damage the plastic wheel. The last method, using a wide enough screwdriver, wedge it in the center of the bearing where the shaft sits and slowly rock the bearing from it’s location. For installation, I will be using the old bearings as I am replacing the wheels completely. Ensure the wheel is clean where the bearing is in contact with. Place the new bearing in place, then use a hammer to tap it into place. Only hit on the outer race or flange, otherwise you may risk damaging the bearing. Continue around in a circular pattern so the bearing installs evenly and does not become wedged. Ensure the mounting shafts are clean and reinstall the wheels. Lower the mower and then tighten the nuts. Finish up by installing the center caps and you’re done.
Step 7: How to Test Engine Compression
Low compression can cause poor performance, poor economy, hard starting, or no starting at all. Low compression can be caused from various faults which I will explain further on in the video. An engine may run on low compression, but it won’t run well. Keep in mind required or acceptable values vary between manufacturers, so be sure to research first.
- spark plug socket
- compression gauge
Remove the spark plug, twist and pull the spark plug wire off. Using a ratchet and appropriate deep socket, remove the spark plug. Plug the spark plug wire off to the side so you do not get a shock when the engine is getting pulled over, especially if you’re using a compressor tester similar to the style shown in the video. With this particular tester, I do need an assistant to pull over the engine as I hold the meter in place. Insert the rubber taper and then pul over the engine, hold the taper tight so we do not risk any leakage. It is best to test the compression at least three times to ensure for an accurate reading regardless of what type of compression tester is used. The first test is about 85psi. Press the button to release the pressure. Next is 80psi and finally we have 90psi. When pulling the engine over, be sure your hands and feet are clear of the lawnmower’s blade too, so you don’t risk hurting yourself. Some lawnmowers such as this model has a direct drive, therefore the blade is always turning if the engine crank is rotating. Now as for issues as to why you have low compression. Low compression is a leak within the combustion chamber, which can be caused by: stuck valves, they can be worn, burnt, or stuck open from carbon deposits. Worn piston rings, damaged piston, or damaged cylinder walls, a faulty head gasket and finally a cracked block, or cracked head. A good engine should have at least 80psi, while a new or very healthy engine will see around a 100psi range but this will vary between manufacturers. When the compression falls past 80psi, this is when we will see issues, especially if they get extremely low
Step 8: How to Test Engine Spark
Poor spark will cause hard starting, poor performance, poor economy, and idling issues. A poor or no spark will also cause no start issues. A blue spark indicates a healthy quality spark, and if the spark were to be a yellow color, this is a weak spark. There are various types of ignition systems available such as points style, magneto, or electronic so parts will vary. But as an overview, a weak or no spark can be cause from various problems such as an improperly gapped spark plug, dirty spark plug, faulty spark plug, faulty spark plug wire, faulty coil or improperly adjusted coil, faulty condenser, faulty or improperly adjusted points, and poor ground. If you have picked up a mower for resale as an investment, some of these parts can be expensive such as an ignition coil. This can easily cut back your profits, so keep that in mind.
- spark plug socket
- new spark plug
Start by removing the spark plug wire, to remove the wire, twist while pulling which will reduce the risk of damaging the wire. Remove the spark plug using the correct socket and a ratchet. When the spark plug is removed, we can use the spark plug to check spark and this will also allow us to pull the engine over easier as there is no compression. I will be showing a couple different methods to check the spark, you will most likely need an assistant to help pull over the engine while holding the spark plug in place. Ensure you have a newer and clean spark plug to work with as this will affect the quality of spark shown. Plug the spark plug into the spark plug wire, then ground out the ground electrode to the engine block, bolt, or a bracket, we want something with a quality ground. Hold the plug by the rubber boot, do not hold the metal spark plug clamp or spark plug because you can risk getting a shock. Sometimes you can set the plug on the ground depending on the configuration or use some type of clamp to hold it in place. Now pull over the engine as if you were starting the engine and watch for a spark, it’s best to work in a shaded area so it’s easier to see the spark. We have a healthy blue spark which is good. As an alternative we can also use a spark testing tool which is similarly designed to a spark plug but has a tubular style ground case. Connect the clamp to a sufficient ground source and continue to pull the engine over, watch for a spark. A blue spark indicates a healthy quality spark, if the spark were to be a yellow color, this is a weak spark. Even though the spark is functional outside the engine, that doesn’t necessarily mean it is operational within the engine under compression. Other spark testers are available where you do not need to remove the spark plug, has an adjustment of the spark gap, and contains the spark within a clear inspection window.
Step 9: How to Sell a Lawnmower
Both mower were posted on local classifieds and that was more than one website as well. One was a generic classified website and another was a local newspaper, both were free to post. You don’t have to be limited to an electronic version either, even print out some ads and post them up at a local gas station or grocery store. Even use Facebook classifieds or social media in general, maybe a friend of a friend is looking for a lawnmower?
- classifieds accounts
- social media accounts
Take high quality photos which represent the mower accurately. Take a one minute video of the mower running and upload that to YouTube. Write a descriptive ad. Include what has been repair, any maintenance which the owner does not have to worry about, new parts, what it may need, running and visual condition, model, horsepower, accessories, etc. Proof read, check grammar and spelling. Include the price, if you are flexible, where you are located and if you offer delivery.
Step 10: How Much Money Did I Make?
Luckily enough, even though it’s at the end of the season I did manage to sell both mowers. I did post them on a local online classifieds and saved both ads to give you an idea how they were laid out, I did cover my ads in the last video, how to promote selling them with a descriptive ad, high quality photos, and video. Both mowers were obtained for free as one was being thrown out and the other was given away as the owners were moving. For the first mower, it was a 21” Craftsman push mower with a 6.5hp Briggs and Stratton engine. The other was a 6hp Tecumseh 21” craftsman push mower that came a couple weeks after. Two lawnmowers, a real life situation and can both be repaired in one day. As mentioned before, this is a great way to make a little cash on the side, whether you’re going to school, want to fund a project, or learn the value of money. Eventually you can work your way up to larger items, investing more money, but also making a greater profit. Even after you gain some experience, you can open yourself up to other opportunities such as repairing small engines on the side too. The possibilities are definitely endless.
Runner Up in the
Fix It Contest