Yanmar 4JH4E - Troubleshooting of Fuel Injection Pump

6. Fuel Injection equipment
236
6.3.7 Troubleshooting of fuel injection
pump
Complete repair means not only replacing
defective parts, but finding and eliminating the
cause of the trouble as well. The cause of the
trouble may not necessarily be in the pump itself,
but may be in the engine or the fuel system. If the
pump is removed prematurely, the true cause of
the trouble may never be known Before removing
the pump from the engine, at least go through the
basic check points given here.
Basic checkpoints
• Check for breaks or oil leaks throughout the fuel
system, from the fuel tank to the nozzle.
• Check the injection timings for all cylinders. Are
they correctly adjusted? Are they too advanced
or too delayed?
• Check the nozzle spray.
• Check the fuel delivery. Is it in good condition?
Loosen the fuel pipe connection at the injection
pump inlet, and test-operate the fuel feed pump.
Note:
The expertise and facilities are necessary for the
disassembly and adjustment of a fuel injection
pump. Make a request to ZEXEL service shop
for them.