John Deere JS40 Steel-Deck Walk-Behind Mower

John Deere JS40 Steel-Deck Walk-Behind Mower

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Not perfect, but pretty doggone good.

Sep 25, 2007 (Updated Jul 11, 2011)
Review by  
Rated a Very Helpful Review
  • User Rating: Excellent

  • Ease of Use:
  • Durability:
  • Noise Level:

Pros:Starts very easily. Plenty of power for the job.

Cons:You have to fiddle a bit with the self-propelled speed adjustment.

The Bottom Line: For the money, you won't find anything better. And you could spend more money without getting a mower this good.


UPDATE: After 3-1/2 mowing seasons, the self-propelled belt finally wore out and snapped. Apparently you must buy these belts directly from John Deere, but through a local dealer. I ordered the belt online, for pickup at the closest dealer. They could not have been more helpful.

Replacing the belt was a little dicey. If you follow the factory directions there is a lot more disassembly to do than what I did. Since the belt is wider than it is thick, there were several spots where I managed to twist it a bit and get it past a spot where the manual calls for removing a part. Worst part is the drive pulley, on the engine shaft above the blade. A pair of rods attached to the motor mount bolts keep the belt from falling off the pulley, and the bolts had to be loosened to install the belt there. I lost my way a bit with the routing of the belt between the engine and transmission. Fortunately the online owner's manual shows how the belt is to be installed.

The whole thing would have been easier had I some place to work on the mower other than lying on the ground. But with all the confusion and feeling my way along, I got the chore done in just over an hour.


John Deere JS40 mower


I've owned more than a dozen different gasoline mowers over the last 33 years--everything from LawnBoy to Toro to Snapper, and some cheapies as well. This John Deere is far and away the best of the lot, although it's not perfect.

We have nearly 10,000 square feet of lawn, but it's broken up by numerous flower beds, a patio and a large parking pad. This is a lot to mow with a walk-behind machine, but too complicated for any kind of rider, even a zero-turn type. It's up and down hill too, which means a self-propelled mower is a must.

I'm not fanatical about lawn care, and we travel by RV, so there are times when the grass is 8 or ten inches high before I mow it. I'm also not meticulous about maintaining mowers, and have often let one sit for too long with stale fuel in the tank, to my great irritation and inconvenience.

I chose the John Deere because it uses a Briggs & Stratton engine. Some of my other mowers have had Kawasaki power, which is fine when it's working. But the Japanese engines have complicated, expensive carburetors that get out of whack frequently, especially with stale gasoline.

The current series of Deere walk-behinds have a little gizmo on the underside of the gas cap that dispenses a drop of fuel stabilizer now and then. All you need do is make sure that replaceable capsule is full, and fortunately they are sold in two-packs. With stabilized gasoline, the engine starts easily. When I filled it the first time, it took only two pulls to get it running, and now it almost always starts on the first try. The starter rope pulls easily, in spite of the fact that, as with all new pull-start mowers, it’s routed up to the handlebars, requiring you to hold down a dead-man to keep the engine running.

There are no throttle and choke controls. The engine runs at a fixed speed, presumably at the peak torque point. You use a rubber priming bulb to start the engine when it’s cold.

The mower is boxed with the handlebars detached, but it took only about five minutes, with no tools, to get it assembled.

This particular model has its front wheels on swivel casters, which is why I chose it. Our flower beds have curving edges, and I reasoned that it would be easier to follow these curves with the swiveling wheels. That has turned out to be not especially true, but I’m glad I chose the swivel wheels anyway, for the most part. A lever on the left side of the handlebar enables me to lock the left-hand caster from swiveling, and that, as it happens, is the easiest way for me to follow the bed edges, with the fixed wheel against the edge. Swivel wheels work fine as long as you are on even ground, but if you run over a little dip, the wheel can swivel in the wrong direction, requiring a little fiddling to bring it around straight. But the swivels make it much easier to turn at the end of a strip of mowing, and that in itself is a great help. My largest patch of lawn is a big rectangle, but the grade requires me to mow it along its short side. It takes about a hundred “laps” to finish this area, and the ease of turning the swiveling wheels is a huge energy saver for me. One drawback of this setup is that it increases the overall length of the mower by almost ten inches. So there are some spots that require either finagling the direction of approach, or hand trimming, because you can’t butt the front of the mower deck right up to a hard edge.

This mower has rear-wheel drive, and while shopping I noticed there are a number of others on the market with front-wheel drive. From experience with both kinds, I can tell you that rear drive is the only way to go. Too often with a front drive mower, you will find yourself stuck somewhere with the powered wheels out of contact with the ground.

The JS40 can be used as a mulching mower, a side-discharge mower or a rear-bagging mower. All the parts are included. To change from one configuration to another requires removing one toggle nut (no tools required) and slipping the proper chute into place. I managed to lose the plastic toggle nut in the first hour of mowing, but the “hell box” in my workshop yielded a nice, big brass one that replaced it readily. That’s another advantage of this brand: it appears to use US (fractional-inch) hardware, rather than metric. While I do have a metric “hell box” also, my collection of SAE fractional-inch nuts and bolts includes stuff accumulated by my grandfathers, so you can almost always find a part that will make do. The metric junk box goes back only about two decades, and it’s in the process of becoming ripe for whomever will inherit it from me.

This mower has only two genuinely annoying points. You drain the oil through the fill plug, rather than a crankcase drain. This has become pretty much par for the course for mower engines, but I don’t like it because you need to empty the gas tank before tipping over the mower to change oil, unless you want a real mess on your hands. On the other hand, the Briggs carburetor is a simple affair without a float chamber, so you don’t end up with a flooded carb when you’ve put the mower up on its side for an oil change, blade change or underside cleaning.

The other annoying bit is the wheel drive mechanism. Deere calls this a “continuously variable speed” drive, which is a nice invention from the marketing department. Any wheel drive on a walk-behind mower is bound to be a bit of a Rube Goldberg contraption. The maker has to figure out an easy way to harness the power of the vertical shaft engine, and make the power “turn a corner” to rotate the horizontal wheel axles. This particular John Deere mechanism involves a v-belt that attaches to the engine shaft just above the mower blade, and runs out through a slot in the deck to a couple of pulleys. Luckily it is self-adjusting for just about the life of the belt, because the part above the deck lies underneath a shield that is held on by six or 8 screws, and is a pain in the neck to remove and replace. The drive speed is controlled by allowing the belt to slip to a greater or lesser degree over a pulley. You have two controls on the handle—one that varies the belt slippage (and thus the speed) and the other that simply engages and disengages the wheel drive. The latter, you have to hold down while you are operating the mower (along with the deadman for the engine). What makes this ANNOYING is that as you allow the drive belt to slip to slow down the mower, it also transfers less torque to the wheels. So, if you are mowing a pattern where you are going downhill, then turning and coming uphill, you must fiddle with the drive speed a bit each time you change directions. It’s a minor annoyance, but one that I noticed immediately. Still, this kind of speed adjustment is far better than the kind where you have to lean down and change a lever down at the mower deck.

It’s also worth mentioning that the wheel height adjusters on this machine are easier to operate than most, and thus far they have not shown any tendency to slip out of adjustment. This is a problem I’ve had with other brands of mowers, especially as they age.

Also, the mower industry seems to have changed from rating engines in horsepower to rating them by torque production. So, I don’t know quite how to compare the power of this mower to the Briggs-powered MTD one that I bought three years ago. Suffice it to say that I have never found the Deere to be short of power, even when plowing through grass that has been let go too long.

I’ve been using this mower for four or five months now, and I’m not sorry I chose it. You can spend a lot more money for a walk-behind mower without getting the features this one has.


Recommend this product? Yes


Amount Paid (US$): 600

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