Winter is here. The winds are blowing, and at meteorology stations across the country, the mercury is dropping. Whether you’ve got snow or not, you probably want nothing more than to sink into a reclining chair with a cup of hot cocoa. Well, by all means do so, because while you’re nice and cozy warm, it’s a great time to do some thinking.

After all, you’re not the only one in hibernation mode. In all but the warmest regions, the nation’s mowers are taking a long winter’s nap, too. Come spring, some will wake up like lambs, ready to be herded out onto fields and gobble up grass. Others will wake up like lions, and need a bunch of extra taming before they can be set loose on an unsuspecting public.

How much work it’ll take to get them up and running depends on how each mower was maintained, and how they were put to bed. In the rush of the busy season, it can be hard to find the time for refining your maintenance plans. So take the time now—sit back, sip your cocoa, and think about whether your fleet might be in need of some more TLC.

To start with, think about any of the ways your fleet has changed in the past year. Have you brought in any new machines recently? Electronic Fuel Injection (EFI) engines have made major inroads in the market of late. Many mower manufacturers launched models prominently featuring this new technology, and perhaps you’ve been thinking about buying one. It’s worth considering how this might affect your maintenance routine.

To get a better idea of just that, I talked with some of the people in the know. Tom Person is a senior test technician with Exmark in Beatrice, Nebraska, and he says that EFI engines and carbureted engines are largely the same when it comes to maintenance. “The differences between them lie in the sensitivity of the engine. An EFI system needs a constant fuel pressure in order to run properly,” he said.

Keeping up that constant fuel pressure won’t happen if your mower has a dirty fuel filter. With a carbureted engine, you can delay a fuel filter change at the risk of accumulating debris in the fuel lines and abbreviating the machine’s service life. In an EFI engine, that gunk in the fuel lines will lower the fuel pressure, and the Engine Control Unit (ECU) will compensate. This will help protect the engine from damage, but it’ll mean a loss of power, which can render the machine inoperative.

Air filters are similarly crucial. A carbureted engine that’s clogged and isn’t getting enough air will run rich, and black smoke will shoot out of the exhaust. EFI machines don’t have that telltale sign, and simply lean out the engine to compensate, again at the cost of power.

That increased sensitivity isn’t just a burden, though. It can be a real boon to your maintenance plan. EFI is made possible by an ECU, a little computer that collects and organizes all the data from your engine’s sensors. The ECU uses that data to optimize engine performance, and so it knows the expected values for each sensor. When one exceeds the acceptable range, it reacts to protect your engine, and trips a trouble code.

A technician with diagnostic software can then hook into the ECU and use that trouble code to figure out the problem. “For example, they check the code on their laptop and it shows code 1234,” said Person. “The software then says, ‘Check this wire at this pin location, and select the appropriate voltage. Is it greater than five volts or less than five volts?” With each question, the software rules out problems. “You just keep digging down parametrically, until you get to the real issue,” Person said.

The ECU is useful even when there isn’t a specific trouble code. According to Scott Mack, senior training specialist for Kohler in Kohler, Wisconsin, if the machine still runs, it can spit out performance metrics. “We have live data that we can see while the engine is running,” he said. “If the dealer understands what that data is supposed to look like, he can identify the problem pretty simply at that point.”

For Mack, the chief maintenance change from EFI comes when winterizing a machine. “Because the injectors don’t get air in them, the fuel inside doesn’t evaporate; it doesn’t get stale like it would in a carburetor,” he said. Even so, you’ll still want to lace your fuel with a stabilizer over the winter. EFI shuts air out of the injectors, but that doesn’t stop the clock entirely, just slows it down.

Mack’s recommended winterization regime runs like this: stabilize the fuel, run the machine for a bit to get the stabilized fuel mixed all through the system, then fill the tank. Over the winter, your fuel tank can ‘breathe’ as temperature fluctuations expand and contract the tank.

“That will bring in air with moisture, and let out vapor, which is not a good thing,” he said.

Filling the tank to the brim reduces the amount of air that’s available to react with the fuel and helps break it down over the months of idleness. Combined with a stabilizer, any separation or residue that may occur should be sufficiently limited so it shouldn’t cause problems in the spring.

There is another way to winterize, but it’s difficult with a regular engine, and not recommended for EFI systems. Running the mower until it’s completely out of gas should mean that there’s no fuel to go bad in the first place; unfortunately this isn’t always the case. There are plenty of mowers out there without a drain for the gas tank and without that, it’s hard to make sure there aren’t any dregs which can break down over the next few months.

What really gets Mack on his soapbox, though, is ethanol. “It absorbs moisture from the air, and between moisture and oxygen, that’s what really breaks down fuel and causes bad things to happen.” The best thing to do is avoid it entirely, especially when winterizing, but in certain parts of the country that’s easier said than done. You can still stabilize it, but it’s more of an uphill battle.

Kent Harlan, owner of Kent’s Lawn Service in Beatrice, Nebraska, says that avoiding ethanol fuels is probably the biggest part of his maintenance plan. “For us, ethanol fuels only cost 20 cents per gallon less than fuels that don’t contain ethanol.” For him, the low price just isn’t worth the trouble. They also filter all their fuel before it goes into the machines, and change their fuel filters once a year. Harlan figures that all those measures are what keep them from having fuel-related problems.

His aggressive approach to maintenance extends to the oil levels of his machines, too. “If somebody starts one of my mowers without checking the oil, we’re gonna spend the time to chew them out before we go to work,” he said. But that’s just the start. All the oil is swapped out every 300 hours, and they use OEM brand synthetic oil religiously.

It’s all part of Harlan’s overall maintenance strategy, avoiding the can of worms that’s opened up when lackluster components or lackadaisical care causes something to break.

“That’s one reason we run OEM synthetic,” he said. “If the day comes when I smoke an engine, whether it’s the manufacturer’s fault, my fault or nobody’s fault, they’re gonna ask me a couple of questions.”

Those questions will be about the nature of the fuel, and how good his maintenance is. This way, Harlan eliminates the possibility of the manufacturer having any lingering doubts about the quality of care his fleet gets.

So how much does this self-built ‘insurance policy’ cost? Well, the answer will vary based on region and fleet size, but Harlan estimates that buying only OEM oil costs him about $4 more every hundred hours. He figures that it’s cheap for what he gets in return. It’s not just the manufacturer’s goodwill; Harlan finds it cuts down on issues. “We probably spend a little more money when we go to do the maintenance, but we just don’t have the problems.”

He even avoids generics and aftermarket parts when buying replacement components. “We got 436 hours out of our original set of blades on one of our mowers,” Harlan said. They got brand-name replacement blades from the dealer, but the new blades didn’t last half as long. “We did that once; we won’t ever do it again. We’ll pay more money for a better quality blade because of the longevity—it saves us money.”

That said, there are a couple of places where Harlan will make some aftermarket upgrades. One is the battery. When the time comes to replace your mower’s battery, bigger is better, and being penny-wise is pound-foolish. “There’s only $10 of difference between a 220 cranking amp battery and a 350 cranking amp battery. We’ll get far more service out of the bigger one; we don’t replace the 350s very often,” said Harlan.

Another add-on gets included before the mower even sees a day of work. He fills his tires with a green sealant called Slime. It cuts the 30 to 40 tire plugs he used to need every season down to two or three. “We way overdo it,” Harlan said. “They typically recommend two or three pumps; I’ll put in eight or ten, because the cost to make sure there’s plenty of slime there is definitely worth it for me. One flat tire will cost me way more than $4 or $5. It’s the lost productivity.”

And there’s the rub. The real cost of deferred maintenance isn’t counted in expensive replacement parts or billable mechanic hours, but in lost opportunities. When that machine is sitting on the blocks, it isn’t out in the field, earning you money. If you haven’t made an arrangement for a replacement machine, you’re watching the grass grow when you want to go out and mow.

Better to avoid incidents entirely by listening to the people who know the machines. Person said that if he had to give one piece of advice, it would be about the importance of early maintenance. “Change that engine oil within the first ten hours,” he said. “That is absolutely critical to the life of that engine.”

He gets asked all the time about the proper service intervals for engine oiling, and what oil you can use.

But mowers are more than just motors. “Probably equally important as engine oil is transaxle or transmission oil,” said Person. “That’s what makes hydrostatic transmissions live.”

Blades need to be sharpened, decks cleaned, and tire pressures evened out. “Don’t just focus on the engine,” Person said. “The whole machine needs equal maintenance; there are other systems that are equally as important.” Gearboxes need their oil changed, pivot points need to be greased, and transmissions have their own filters that need to be replaced.

Every company has a different fleet, and every fleet has its own needs. Although a maintenance plan may start with the manufacturer’s published guidelines, it doesn’t end there. Personalizing your preventative maintenance plan to better account for your most common and expensive problems is just smart business. You’re already taking care of your machines, and just that little bit of extra effort can pay huge dividends.

The automotive market is the main driver of engine progress, and it can take some time for those advancements to permeate into the mower market. Because of that gap, it can often seem like maintenance is static: you take mower X, put in regular effort Y, and get out service life Z.

However, even slowed, the march of technology is still progressing, and will bring changes to what your machines need, whether you’re ready for them or not. Keeping up with the latest and greatest isn’t just exciting, it’s prudent. Your drive will keep your business running, but foresight will keep your mowers running.