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Show AUTO LESSON Ko. 121. Locating Tronble. Iri 'iho a3t few Iciisona you were told ..ov. nnj one of "the throe essentials ' ' could cause engine trouble. This gives you a foundation for properly going about the locating trouble. Trouble locating is series of elimination. elimina-tion. ;he eliminations being based on reasoning and testing. Engine troubles might be classed as 01 four kinds; namely, engine will not start, engine stops while mnning smoothly, engine misses, or engine lacks the troubV: ia due to the feed of the gasoline to the carbureter. If "Ko," then we must look further. Can ignition have failed Yes. Has the car vibration jarred our switch open? No. Is there any reason why the battery should be dischard! No. Did the car stop suddenly before as it has jnst done? Yes. What was the cause that timet Why, so-and-so. Is that the cause of the stopping now! Let us get out and see. (From this paragraph you can sec the wisdom of alwa3's knowing what it waa that caused the trouble, and the remedy I L 1 P&ver. Let us see how to find th? cause of the engine stopping. Suppose the car has been runniny along finely at a good clip and then, suddenly stops. What would you do.' l-,;r:t of all we would think of i'ne three essentials, namely, compression, mixture and ignition, and then reason or t;iik to ourselves somewhat follows: fol-lows: Can compression losa be the cause of the stopping? No, all four cylinders will not lose their compression suddenly sud-denly and at the same time. So compression com-pression is eliminated as a possible cause. Is mixture tronble the cause? It might be. Have we gas in the tank? Yes. Is the gasoline feed system working work-ing O. K.t Apparently. Was there a popping in the carbnreter before the stopping of the engine? If "Yes," then we can be reasonably sure that therefor, as it is quite possible that the trouble may again develop.) Having failed to locate the trouble by reasoning, what shall we do next? First run over the wiring quickly and see that none has come off or is short-circuited, short-circuited, examining carefully all places T.7herc wires cross or rest against parts of the car, as the insulation may have worn off at one of the; plaees. The examination failing to show the tronble, what shall we do next? Compression Com-pression being eliminated, we must see whether the ignition or mixture has failed. Let us first check up the ignition. igni-tion. Howl When our engine is running, run-ning, the surrent runs through tho wiro from the distributor to the spark plug and then gives a sparf; by jumping across the gap of the plug to tho grounded portion, so if we were to take or..'; of the .wires off the plug and hold it about an eighth of an inch from rne'nl of the engine, we will see a spark if the ignition is O. K. when some one cranks the cogine for us. Thus the first test to make is to take one of the wires front a plug, hold it about an eighth of an inch from tho CDgine and get someone to crank the engine. If we get, a spark, tht:n we know that tho ignition is O. K. and that tho trouble trou-ble is duo to the mixture. If w do not get a spark, we know that tho trouble is in tho ignition system and can forgot about tho mixture. Suppose we did Rot a spark. We know now that mixture is the tronble. Is it the adjustment? No. Tho adjustment ad-justment will not go wrong suddenly.! so wo will not touch tho adjustment screws. Are wo getting gasoline to the carbureter? Let us hohi down the primer and flood tho carbureter. If it will not flood or takes a long limn to do so, Iheti wo know that tho trouble is in the feed as given in a. previous lesson. If it does flood, what then? It is pos'iible that the float was stuck and we freed it. so let us test it by U:cing if the engino will now run. If not, what then could be the trouble? I f'us'ubly water htm gotten info the ga-solinc. so lot as drain, tiui carbureter and fill it with a fresh supply of gasoline gaso-line and see if it will then run. We mnv even have to pour some raw gasoline gas-oline into the cylinders through tho compression cocks. Sometimes, though rarely, the carbureter car-bureter will come loose from the manifold mani-fold due to the bolts working back, and thus allow extra air to got into tlo mixture, in this way weakening it so as to cause a complete stopping of the engine. You will bo able to feel this looseness. If the trouble is due to the mixture the above method is sure to locate it. Let us assume that we failed to get a spark and see how wo must proceed. Where the engine suddenly stops we need not touch tho spark plugs, as all four will not go bad suddenly. By the sarno reasoning we know that tlie wires betwrvn tho plugs and the distributor cannot be at fault. The main pecondary lead, however, may be the cause of the trouble, and if it is, it probablv is due to a short circuit. After tracing this lend we must trace tlv wire from the coil to tho ground, and thuH complete an examination of the bceondarv. Ft would bo well to look at the distributor also, but this, unless broken, is seldom the causo of trouble. (Caution, t'ome distributor brushes do not mako an actual contact with tho segments.) Having satisf'.-d ourselves that tho secondary is O. K. and an examination of tho wires of tho primnry disclosing nothing, our trouble is either duo to wire being broken inside its insulation, of to a failure of one of the units. Wo must, therefore, now hunt by making mak-ing Irsts. For this purpose it would be well to carry in vour tool kit a testing test-ing lamp, .is shown in tho Illustration. This can also bo used h a troublo lamp to give light at nifht. Tho systematic trouble-hunter is the quick tronble f inder, so tho next thing to do is to determine IN' ordor of tho unit in the eircnit. Let uh assume flint wo havo a distributor system in which tlm ri'rrf"' t SiUuM Uiij Im Hunt to the bwitch; then the coil, then the interrupter in-terrupter aud back through the ground to the batterj'. We would first then test the battery, by holding one wiro of our testing lamp to the positive pole of the battery, and the other to the necati'..-. If the lamp lights the battery bat-tery is O. K. If it fails to light, the battery is tho trouble. As the connecting connect-ing links between ihu various cells may have become loosened wo will have to try thjm. The next stop would bo to test each cell, as one may be bad. Should this bo the case this cell can be cut. out and the romainint! cells will probably give enough current to get us home. In tho case of a discharged dis-charged storage battery, dry cells can be substituted for it, but when this is done tho generator must be disconnected. discon-nected. The battery being O. K., we will noxt test, between the battery and the ground; thus, if tho positio of (lie batlerv is grounded w e will hold one wire of the test i ng la m p against, the negative terminal of. tho battery and the other against, .souio clean uvtal part of tho fngjue or frame. This will tell us whether or not tho grounded wiro ia broken or tho connections bad. The ground being O. K. we will nrxl hold one wiro of the testing lamp against the ground and tho oilier against tho terminal post of tho swil.cn where tho wire from the battery is connected con-nected to it. After testing the wiro to the switch wo will test the switch, by holding one of our testing lamp wires against thn binding post at. tho switch for the wiro which goes to tho coil, aud the other cud against the ground. If the lamp fails to light, the switch is at fault, as we saw thai we were getting get-ting current to it. After testing the switch we cau test in the same way tho wire going into the coil, that coming com-ing out and that, connected to tlwi interrupter. in-terrupter. In testing the interrupter, tho breaker points must be set so as to be in contact. fcUiouIil LUi lamp Light at all these. points tluo trouble is in tho interrupter, ami wo must, bo sure that the poiutM are opening anil closing properly. Should you have made tho np:irk !o.t to see it the iniliou was U. K. ami have Kolteu a spark, ami. at the same tiiuo l'''i certain thai the mix ture ii not at fault, then you will hae to look for a break or a. slipping of seme part of the engine, l-'or example, the distributor mnv have slipped on its shaft and thus caused the spark to be out of time. "YIumi this happens it will ho n-ccompanicd by n series of carbureter car-bureter and muffler explosions as a rule. |
