| Show proper type spark plug most important factor to maintain engine per forti once in cars buses or trucks it x Is essential that the proper atia spark plus be used the same type spark plus plug will not meet all drang conditions and all re mutable 0 include in their ines many different diner ent types or spark plugs tv to meet different ing conditions attention to tile mat ter of the proper selection ot of spark plugs for or particular perylee pen ice go a long way toward insuring trouble free performance forni for mance ance an illustration 6 of aills point Is cited in tle tile celse of a bus that had been operated P e rated with complete satisfaction on a level route but whon when tt it was transferred to a dIf different terent route where practically ily all of the highway was alliy country cou the engine de v eloped the difficulty wan vats immediately corrected with the spark plugs of i a cooler ype specially spec lally designed desIgn ea to overcome 1 t t |
