A very small diesel engine launch requires three things, all of them. First, the air to be inhaled to form a strong swirl, in the compression endpoint than diesel ignition point higher than 200 ~ 400 °C compression end temperature, that is, up to 500 ~ 700 °C; The second is to inject the diesel fuel into the combustion chamber at high pressure, and the third is to rotate the crankshaft faster than 110R Min-1. Thus, the main trouble spots causing very small diesel engine startup difficulties include compression system, fuel supply system, valve train, and starting device. For the start-up difficulties, we only need to look at these aspects carefully, we will find the fault.

1. Insufficient cylinder pressure

Insufficient compression pressure in the cylinder will cause the temperature in the cylinder to be too low, the diesel fuel is difficult to burn and causes the start difficulty. Specific reasons: (1) air leakage of the intake valve or exhaust valve, valve and valve seat sealing ring belt pock, cavitation, and burning damage to the valve leakage. Check the valve assembly is normal, re-repair the hinge, grinding valve, restore the valve sealing, and adjust the valve clearance. (2) the piston and the cylinder sleeve are not well-matched, resulting in air leakage. Check the wear condition of the cylinder liner and piston, if the wear exceeds the limit, it should be replaced. (3) the valve rod is stin the valve guide, which is mainly caused by carbon deposition after after burning engine oil. Remove valve stem, remove carbon deposits, clean and reassemble, and replace valve and valve guide if necessary.

2. Fuel system failure

The fuel quality, atomization quality, injection pressure, and injection time of the fuel system all affect the start-up performance of a very small diesel engine. The specific reasons are as follows: (1) the angle of the advance of oil supply is not right. (2) the oil quantity tie rod is stin the stop oil supply position; the adjusting gear ring and the adjusting gear rod are st the plunger is stin the stop oil supply position. At this point should be dismantled, check whether there is dirt st clean with clean diesel oil; check whether there is damage, Burr, repair. (3) the fuel injection pump does not supply oil or the fuel supply is abnormal. Repair or replace the new couplings should be removed and adjusted on the fuel injection pump test-bed.

3. Low starting speed

A very small diesel engine starts with a minimum speed of the crankshaft, and if the starting speed of the system is too low, a very small diesel engine will not start. Specific reasons: (1) poor circuit contact, loose joints; (2) insufficient battery capacity; starting motor power decline; (3) starting motor failure.

Check the exclusion method: (1) check whether the starting device is working properly, the line of the connection point is tight, tighten the connecting pile head or thread head, if necessary, grind repair posts so that the wire contact is good; (2) charging the battery; troubleshooting the starting motor; (3) removing the starting motor and polishing the rectifier with fine sandpaper; the spring force of the carbon brush holder is insufficient and should be replaced.