POOR RUNNING

Timaru Herald, Volume CXXV, Issue 18629, 26 July 1930, Page 10

POOR RUNNING

AT LOW SPEEDS. Poor running at low speeds is itself a sign of the want of decarbonisation; the valves have probably become pitted and need regrinding, which is really much more important than the removal of the carbon deposit from cylinder and pistons which, as a rule is the accredited reason for taking off the cylinder head. Everyone will readily conceive that even running must depend very largely on steady flow of gas from the carburettor. It is easy to understand then, that air leaks must be harmful. If we have air entering the induction pipe in uneven quantities it implies that gas must be caused in the gas stream with the result that a cylinder here and there is starved of mixture. The induction pipe manifold therefore, is a possible delinquent, and one should make sure that the nuts are tight, while as much may be said for the joint between the carburettor and induction pipe. Air leaks bring us back to the valves again. If an engine has done many, many thousands of miles it is just possible that the inlet valve guides may become worn and allow air to be sucked in with the inducted charge. A new guide or guides may, therefore, be necessary on very old cars. The magneto quite often can be the cause of irregular firing at low speeds. Badly adjusted contact points can be responsible, as can also those that are worn or very badly pitted.