Several factors can contribute to petrol engine’s high-starting, it is important we deal with such factors for the purpose of helping anyone that would be making a troubleshooting of high-starting in any petrol engine.
An engine can be said to be having high-starting if it does not always start the first or second time the main shaft rotates, the rotation can be done manually with a rope fixed at the flywheel attached to the outlet of the main shaft or automatically using an electric motor.
High-starting in petrol engines had been a common problem especially in generators, the major issue that everyone usually points hand to; is the engine plug; but beyond that, let’s highlight other factors that could actually give rise to such problem. Engine plug usually located just above the piston or by the side of it, depending on the engine design. It had been known as known as a common source of a petrol engines high-starting problem.
The plug can cause high starting when the sparks usually supplied to the combustion chamber have reduced, such that the sparks will no longer be sufficient to ignite the compressed air-fuel mixture in the combustion chamber, for this reason; the air-fuel mixture needs to be in higher volume to be able to ignite the engine with such low spark plug. But beside the engine plug, there are other factors that could cause petrol engine high-starting;
Dirty combustion chamber: this is a situation in a combustion chamber, where carbon monoxide burnt sticks on the walls of the internal combustion chamber thereby blocking or reducing the flashpoint of the compressed air-fuel mixture in the engine, and such can hinder the mixture to make a quick ignition even when the plug is giving out sufficient sparks.
Leakage in the compression stroke: every four-stroke engine has compression stroke, it is the stroke where pressure is built in the combustion chamber due to the compression of the air-fuel mixture as the piston is going upward, the high pressure coming from the compression raises the temperature of the air-fuel mixture helping it to make a quick ignition once the plug releases its spark. However, if there exist any source of leakage in this system it will reduce the pressure and temperature in the chamber and hence make it difficult to catch up with the sparks from the plug, even when the plug is in perfect condition. The leakages coming from the chamber can be as a result of faulty piston rings, faulty valves (both inlet and outlet valves), etc.
Carburetor problem: carburetor plays important roles in petrol engines, it is the part that sucks air and mix it with the fuel coming from the fuel tank in an atomized state and delivers the gaseous mixture to the internal combustion chamber through the inlet valve, but if this part of engine has fault it can affect the starting of engines. The common problem of carburetor that can cause such, is when its check valve is not open enough to make a good and accurate mixture of the air and the fuel, in a situation where the air is more than the fuel beyond the stipulated ratio, the internal combustion chamber will be suffering from insufficient fuel to cause a combustion from the plug sparks, hence; high-starting will become inevitable.
Beyond the above mentioned possible causes of high-starting in a petrol engine, there may be other minor factors but such is usually rare. It is important to check the above-listed problems first before any other area.