The worst way to waste time is to try to fix something that doesn’t need fixing. Determining exactly what ails an engine is an exercise in logic called “troubleshooting.” Within the equipment limits that even professional mechanics must work, there is always a certain amount of supposition and guesswork, but the good troubleshooter keeps his guesses to the minimum and tries to make the most effective check with the least expenditure of effort. 

You must accept the fact that you will not be able to troubleshoot every conceivable problem. Every small gas appliance has some particular widget that can fail in some unusual way, and only the man who services these units on an everyday basis can hope to keep up with even a majority of the possibilities. What you can expect is to be able to find the routine causes of failure, the ones that account for 99 percent of the problems. 

Although most of this chapter consists of troubleshooting charts, several of the popular items are discussed separately from the charts. You must understand that charts are merely memory jogs, to remind you to check something that you already know about. A chart can’t find the trouble for you. If you see that “choke partly closed;’ is a possible cause for a problem, you must know how to check this possibility. To do this, you may have to do more than just pull the choke linkage to the open position. You should also know how to find the carburetor and know which plate in the air horn is the choke, in order to cover the possibility that something is wrong with the linkage or its adjustment. 

You also must be able to tell when something’s wrong by looking at it. A clogged air filter, for example, need not be black with dirt. If you’ve got sandy soil, that filter may look as if it just rolled off a production line, and yet be plugged. A fuel filter also can look clean-and actually be clean-but if it’s water-logged because you didn’t run the last bit of gasoline through when you packed away the machine for the season, it’s just as plugged as if it were filled with dirt.

 Can’t tell? Not sure? You probably cannot take the time to master the trade of small gas engine service. All you want to be able to do is make most of your own repairs and keep the machine going as long as possible. There are times when you will have to take the appliance in for professional service, but if you keep cool and think logically, they will be few and far between.

 When you’re not sure, there are often simple little double checks, and this chapter explains them. 

A sound piece of advice is to know your machine and not expect it to perform the way it did when it was new. This is not to say that hard starting and poor performance, stalling, vibration, or other problems are normal conditions that you must live with as a machine wears on. In many cases, careful service and maintenance will keep overall performance reasonably close to new-machine levels. 

Note: Some of the items covered in the troubleshooting charts are not among the sort of things the average homeowner will want to tackle. They are included primarily to make you a somewhat more informed customer when you do have to bring the appliance to a service center. Here are some examples: You bring the appliance in for replacement of crankshaft bearings and soon after it’s back in use, you notice oil leaks. The troubleshooting chart lists three things that could have been done wrong by the repair shop. Or let’s say your engine has developed a performance problem and your checkout discloses that all the easy-to-service systems are in good condition.

 The extremely high probability that one of the major repairs on the list is required provides you with some of the information you need to make an “Is it worth fixing ?” decision, covered in Chapter 9.