If your self-propelled lawn mower has suddenly become a push mower, if it runs rough, or if it won’t even start, don’t panic. You might not need to take it in for service yet. Use these quick tips to narrow down the problem and fix it. Many of these solutions will work no matter if you have a gas, electric, or cordless model.
Here are the three most common dilemmas facing the owners of self-propelled lawn mowers.
1. The mower doesn’t self-propel anymore, or it moves too slowly
This usually results from a problem with the cable that controls the speed. It’s probably the most common complaint about older self-propelled mowers.
Time to complete: less than 10 minutes
If the transmission or drive cable comes loose or breaks, your mower will stop moving forward on its own. Inspect the whole cable from the handlebar down to the transmission. Make sure it’s connected firmly at both ends and doesn’t need to be replaced because of wear or damage. (Rodents love to gnaw on wires, especially plastic-coated ones. If you have uninvited guests in your garage over the winter, you might have a few gaps in your cable.)
If you have a Personal Pace mower and it’s moving too slowly, check the wire cable that runs from the handle down to the transmission. With the engine turned off, squeeze the Personal Pace handle. It should move about an inch before you feel resistance. If it moves more than that, the cable may need tightening. This tends to stretch with wear just like a gear cable on an old ten-speed bike.
Loosen the bolt that clamps the cable onto the handle. Pull up the drive cable about an inch, tighten the bolt, and then squeeze the handle again. If there is less play, test the mower’s speed with the engine running.
Wheels and the drive wheel gears
Time to complete: less than 10 minutes if you don’t have to remove the wheels
Wheels and gears need cleaning and lubrication, and sometimes they just need to be replaced. Your mower will move much more slowly if the drive wheels and gears are jammed up with clippings and dirt. Clean them and spray them with WD-40 or graphite.
2. The mower vibrates too much, makes noises, or cuts poorly
If you have a bent, damaged, or unbalanced blade, it will make the mower shake more than normal. It will also damage your lawn by tearing out grass or making ragged cuts. If you can’t see the ragged cuts now, you will soon enough, as the grass will turn brown at the tips.
Please remember to disconnect the spark plug cable before doing any of the maintenance described below.
Clear out grass clippings and dirt from the underside of the mower. If the blade is obviously bent or damaged, replace it. If it looks okay, but you’re still getting bad vibrations, remove it. Check the balance by using a balancer or hanging it with a nail through its center hole. If one side hangs lower, file that edge until the blade hangs level. Sharpen the blade about every two weeks for the best cut.
Once you’ve removed the blade, you can see the rod, or shaft, connecting the blade to the motor. If you’ve run over large rocks or tree stumps, it may be bent. If it is damaged, we recommend that you take the mower to a mechanic.
3. The mower runs rough, or won’t start
Just like in a car, a bad spark plug, drained battery, or stale fuel can stop a mower from starting. If your mower has a fuel shut-off valve and it’s closed, that could prevent your mower from starting, too. Make sure any safety features (like blade control) that keep the mower from operating are all disengaged. Then try starting the mower again. If that fails, try the steps below.
If you’ve left gas in the tank all winter without using a stabilizer, the gas may have gone bad. Does it smell wrong? Remove all the fuel, change the filter, and then put fresh gasoline in the tank. (At least with self-propelled 4-cylinder engines you don’t have to mix the gas and oil together.)
Time to complete: less than 5 minutes
Disconnect the spark plug cable (but wait, you already did that, didn’t you? Safety first!), pull out the spark plug, and wipe it clean. If the porcelain is cracked or the electrode burned off, you’ll need a new one. Lawn mower spark plugs need to be replaced about once a year. After you put it back, or put in a new one, connect the cable. Does the mower start?
If your mower has electric starter that runs off a battery, see if the battery has drained. Recharge it, or replace it if it won’t hold a charge. Do the same for cordless mowers that run off batteries.
Electric mowers are dependent on extension cords, and those cords are prone to damage. Try a different cord and test the outlet to make sure it’s working.
Carburetor and Air Filter
Clean, or better yet, replace the air filter if it’s filthy. Cleaning a carburetor is a big job, but it’s not impossible. See if your mower’s manufacturer gives advice on how to do it, or else take your mower to a mechanic.
If all else fails…
If your mower is out of warranty and repairs are too expensive, consider getting a new self-propelled lawn mower. See the reviews of the latest and greatest models. Find out what features will make your mowing easier. Read more at lawntoolsguide.com.
Robert Harting says
I too like the out doors .so getting out and mowing my lawn then having a cool beer is my idea of relaxing ..Keep up your good work J..
Mower stopped self-propelling. Started making a “shrieking” noise when I engaged the drive, like a bad fan belt rubbing on something. What might be the problem?
Jay, it depends a on the mower brand and model. Many mowers use a belt to self-propel, so it could easily be a belt if that is the case. But that could be caused by something, like a stick or weed or small rock or something, getting hung up in drive system. I would look at the drive line and wheels to see if I could find something in there that could cause it to stop and making the belts stall. Let me know how that turns out.
Based on number 1, can the transmission cord be replaced? The cord on mine sheared off of the metal piece that attaches it to the power bar. I’d love to know if that can be repaired without buying a new mower.
Lara, yes you can replace the transmission cord in most cases. You will need to check with the manufacturer to see how to obtain one. Thanks for asking.
Mike Bolsoni says
when trying to increase speed on my toro lawnmower–the handle is hard to move from 1 to two and three.Can this be adjusted or lubicated
Mike, it is likely the friction between the cable and the cable housing causing your problem. Certainly apply a little lubricant at the handle part to see if that will fix it. But if not, you might be able to put a little graphite into the cable housing and push it back and forth, adding a little more as you go until it gets in a ways and see if that helps. Otherwise a cable replacement will probably do the trick.
I have a Husqvarna self propelled and was cutting grass fine no problems I shut it off to talk to a neighbor and it never started again after that?? Any suggestions? Thanks
The self propelled function of my Poulan lawnmower just stopped working. The front wheels are moving just slightly and a little irradically. Just happened when I shut the mower off to get a drink of water and returned. Any thoughts?
Vicki, my suspicion is that something got caught in the drive belt. It is odd that it happened like that, though.
M Huprich says
I have a self-propelled mower and the front wheels are the one that are propelled. The right wheel is wobbly. I tightened the bolt in the middle of the wheel but it didn’t change the wobble – it looks loose
There is probably some significant wear on the wheel where the bolt goes through. You will probably need to replace the wheel.
I have a personal pace dual blade lawnmower by toro. This mower is very hard to push, please let me know if there is a way to adjust this. Thanks gio
Joe Fuertes says
my mower start ideling and then stops. This is the 3rd mower I got from home depot. this time I bought the toro brand and it does the same thing. If I tip the mower side ways the mower started running again. It sounds like the gas is not going in well. Any tips how to fixed this?
I have a toro self propel lawn mower and the wheels stopped turning all of a sudden. It turned into a push mower 1year old
Ray Janko says
Don’t feel bad. My Toro 22 inch recycler self propelled is only a week old! Cutting grass for 2nd time today and self propel stopped working after I cut a swath of about 30 feet! Don’t know what happened. Calling dealer tomorrow.
Adam Monahan says
I have a MTD Pro Walk Behind 12A-997A795. I have had it since new. The self propelled lever does not spring back into place when I let go of it. I have looked all over it to see if I’m missing a spring but I can’t seem to find a place where one would go underneath near the transmission.
The speed setting doesn’t stay where I set it. Do the teeth wear out on lever? What I have done, I have replaced all the cables and the belt on the mower and cleaned out all old grass. Running out of ideas, can you help with this?
Can anyone help? My Self propelled lawnmower drive wheel doesn’t stop immediately when I release the handle…any ideas how to fix? It’s a Sterwins mower from France.
Carrie, I am definitely not familiar with that mower. Has it always done that? How far or long does it continue to move after you release the handle? Could it just be built up momentum? Some have a braking device to keep mowers from continuing while others don’t. Anyone else familiar with this mower and have this problem?
Luis B says
I have a Husqvarna selfpropeller 4wd lawnmower , somehow the left side tires are not moving, the right side looks ok, the belt looks Ok although maybe a little loose , any ideas ? Thanks
If the right side wheels are moving then the mechanism that connects to the left side has something wrong, obviously. If the belt connecting them is loose, I would definitely try tightening it.