Repair or Replace 2-stroke engines?



Two-stroke engines: repair or replace?


Many factors come into play when trying to determine whether it is time to replace or repair broken two-stroke power equipment. But before you can make any type of decision in this regard, you must properly diagnose the problem. After all, you need to determine if the equipment actually is broken. For example, have you determined whether the malfunction could be something as simple as a defective off/on toggle switch?

Assuming you’ve determined the problem isn’t some minor malfunction, ask yourself the questions outlined in this article to help you determine when to repair the engine or simply replace your handheld power equipment. This is an issue that arises much more frequently with handheld equipment than with larger types, because extensive repairs often cost more than a brand new replacement.


Question 1: Was the equipment getting the job done?

Though it may seem obvious, this is an important question. Did the equipment fail because it was too small for the job, and your crew stressed it by working it harder than it was designed to work? Was it constantly in the shop for repairs? Or did it only seem like the machine was never available because minor repair parts—air and gas filters—were difficult or costly to obtain and simply kept it out of service?

Question 2: What is the repair cost of the current equipment?

This is important because when repair labor rates run in the $40-per-hour range, the cost of labor for a repair can quickly surpass the cost of a trimmer.

Question 3: Does any warranty remain?

Warranties can vary greatly between manufacturers; some commercial warranties are as short as 90 days, whereas some last as long as 2 years.

Question 4: Who made the equipment?

Was the equipment manufactured by a well-known company, or was it an ”off” brand? Many reasons exist why you should build your equipment inventory from the products of just one manufacturer—and a quality one to boot. For starters, the operation controls will be similar on one manufacturer's line of products, and therefore your crew will learn to use new equipment more quickly. In fact, training to use the new equipment may not even be necessary. In addition, maintenance and minor repairs on the equipment will be similar. Typically, the recommended oils and lubricants will be similar or the same, too. In addition, if one trimmer dies, for example, you can salvage parts from it to use on another. But the No.1 reason to stick with one manufacturer's product line is that, if you've already bought four trimmers from one dealer, he'll probably give you a good discount on the fifth.

Question 5: Why did the equipment fail?

 Was the problem a manufacturer defect or actually the result of employee neglect?

Question 6: Could the failure, or the cause of the failure, have produced other damage that might result in future problems?

Consider this all-too-common problem: about 25 percent of all trimmers fail because someone used the wrong gasoline/oil mix. Thus, it wasn't the trimmer that failed but the gas/oil that ruined it. Think about how likely it is that this type of problem could occur at your maintenance shop. After all, how many gasoline cans sit around your repair area? Are they clearly and accurately identified? Who is responsible for mixing in the correct proportion of oil? (With incorrect fuel, a small engine can self-destruct within 20 seconds.)

Also consider what your crew might do if one of them ran out of the proper 2-cycle oil. Would he or she simply substitute regular SAE-30-weight motor oil? You should hope not because, eventually, such substitutions will cut short that trimmer's life.


A real-world proposition

Considering all of the above questions, let's look at an example and see if you can determine what the proper response to a repair-or-replace scenario would be. Imagine that you purchased a name-brand trimmer three years ago for $350. It has worked flawlessly and never needed repairs. A new employee, however, accidentally uses the wrong gasoline and ruins the engine. The repair shop gives you the cost for a repair. Your options:

A) Replace with a new OEM engine: cost of $250, warranty of 90 days.

B) Rebuild the engine: cost of $125, warranty of 30 days.

C) Sell the trimmer to the repair shop for its parts: receive $25.

D) Keep the broken trimmer.

Which is the correct answer? C, or perhaps D. Why? Let's consider each response.

Answer A: If you chose Answer A, you need to consider more than the high cost upfront that you'll pay. For example, most small-power-equipment manufacturers change their models every year. A three-year-old trimmer is probably no longer being made. Though replacement parts are probably still available, they may not be in a short time. Next year, if your gear case goes out, you'll likely find that it's no longer available. As these disposable trimmers get a few years on them, then, the authorized dealers will stock fewer of their parts. If and when this trimmer goes into the repair shop, it could be weeks before mechanics find parts.

Answer B: If you chose Answer B, you also could run into some unexpected results. For example, have you had experience with this repair shop in rebuilding small power equipment? Is this an authorized factory repair shop or just a general mower-repair shop? Most repair shops are booked solid from March until June, with waits of 4 to 6 weeks. How long will it take to perform your repair? How long will it take to re-repair the trimmer if the first repair does not work? How inconvenienced will you be without this trimmer while it is being repaired? Once it is repaired, you'll still have the same concern about future repair parts that we discussed in Option A. Even if you decide to replace the engine on an older piece of equipment, you have no guarantee that other parts won't soon fail.

Answer C: This is the correct response because today's trimmers are not designed to be repaired—only maintained. Most manufacturers do not make oversize pistons or oversize bearings. Most cylinder bores are hard-chrome plated and cannot be bored. While some may follow the saying, "Anything can be fixed with enough time and money,” you'll be dollars and days ahead if you ignore this old adage.

Answer D: Answer D might be a good option for some grounds managers. If your facilities have several of the same model trimmers, other units might fail too. When that happens, you'll be able to remove parts from your original broken trimmer to repair other units and extend their life.


Reinforcing your lesson

Let's consider another repair-n-replace example to reinforce what we've discussed. An edger that you've had in service for less than three months experiences a total engine failure from a collapsed air filter. The damaged air filter became bent when the equipment got bumped while being loaded onto the truck. The operator didn’t think that a bent air filter was much of a problem and continued to use the edger. It seemed to work perfectly—-until the engine suddenly failed.

The repair shop found that cracks in the damaged air filter allowed dirt into the engine, which quickly destroyed it. The manufacturer would not warranty the repair because it was not a manufacturing defect. What should you do? In this case, go ahead and put a new engine on the edger. After all, the remaining parts on the edger are still almost new. In this situation, it's worth it to replace the engine rather than scrapping it for parts.

Knowing when to repair or replace power equipment obviously depends on many factors. To make the most cost-effective decision, you must consider all of them and determine which path is correct for you.


Technical credit: Robert Sokol

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