Magazine article American Forests

Tailgate Troubleshooting

Magazine article American Forests

Tailgate Troubleshooting

Article excerpt

There you are, two miles back of beyond, and your chainsaw has sputtered and died just as you dropped her in the cut. I know firsthand the frustration that comes from a balky saw, but a trip to the shop or the dealer may be avoidable. The secret of repairing a chainsaw anywhere, and especially in the woods, is an understanding of how your saw works.

In theory, the saw utilizes three systems that must all work together. Fuel, electrical, and mechanical components need to perform satisfactorily in proper synchronization, and therein lies the first clue to successful stump-top problem solving. The first job is to determine which system has failed.

Once that is done, you've taken a major step toward putting your saw back in operating order. All topnotch mechanics are above average detectives. A problem can't be fixed until it's found.

One note before we continue. Keep in mind that I'll be purposely bypassing simplistic oversights such as an empty fuel tank, an improperly adjusted choke, or a switch in the Off position. For the remainder of this article, I'm assuming that you are a competent operator who has read the manufacturer's instructions and is following them. The problem is not that you don't know how to operate your saw but rather that you aren't sure how to go about repairing it.

Suppose the saw doesn't start despite vigorous effort on your part. The problem is apt to lie with either the fuel or electrical system, not the mechanical components. Repair clue No. 2 is always to check the easiest items first. To me that means the spark, so here goes.

Start by removing the sparkplug and examining it for bits of carbon bridging the gap between the electrodes. Carbon particles prevent ignition by allowing the current to flow from electrode to electrode without having to arc. Also examine the plug for damage. If the porcelain is cracked, the current can exit to ground and will not ignite the fuel/air mixture.

A sparkplug with cracked or broken insulation is useless. Take it home and dispose of it properly. But a carbon-incapacitated plug can often be returned to use after the carbon has been carefully scraped away with some thin tool like the blade of a pocketknife.

Suppose the plug still won't fire, so you've tried a new plug with the same results. What next? Disconnect the On/Off switch from its wire, and place the wire terminal so that it will not be near any metal surface and thus complete the electrical circuit. (With chainsaws, the On switch breaks the circuit and lets you start the saw, contrary to the way the ignition switch works on a car.) If a retest of your plug produces a spark, the switch is defective and must be replaced. However, this doesn't necessarily dictate an immediate trip to your dealer. You can finish the day with that saw, but you will have to choke it to stop it, and restarting may take a bit longer due to the resultant flooding.

Intermittent spark can result when the ignition wire no longer makes a solid contact with the gripping terminal located inside the sparkplug boot. These terminals are of varying design, but this problem can usually be remedied on the spot by reassembling the components, which is often enough to get a tighter fit.

Occasionally, a plug will show spark when tested but will not ignite the fuel mixture. The compressed atmosphere within the firing chamber makes life a bit more difficult for the ignition system because a stronger current is required to arc across a sparkplug's gap under those conditions. Attempting to operate the saw with a spare plug is the remedial method for this situation. If the saw runs with the spare plug, use the spare and get rid of the weak original plug.

Three tips for spark arc testing. Note the color of the spark-blue is preferred over orange. Did the spark appear tentative, or was it sharp and crisp? And finally, how slow can you pull the starter rope and still get a good, reliable spark? …

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