Help needed with start/stop problems with my Lehman 4D61

[joebuz]

The last week in May we were returning from cruising on the ICW in from Alabama to Florida. I was preparing to leave an anchorage in the morning but the 4D61 would not start. The batteries were good, the starter was cranking well, bleeding the fuel system revealed no air, there appeared to be good fuel flow and the primary fuel filter showed no water. In frustration, I finally moved the throttle from ¼ to full open. She started.

Some added info… The glow plugs are activated by a separate button installed by PO. And they were not working (could not see a large draw on battery when activated) that morning. However, the glow plugs had not been working for several days and she always started in the morning. Glow plugs have since been repaired. The problem was a bad electrical connection.

All had been ok until the last week in October when the engine would not shut down with the switch. A light tap on the starter would shut her down. I don't understand that but it worked. I didn’t like stopping her that way so I began shutting her down by manually shutting off the fuel at the injector pump.

I replaced the starter switch, but the shutdown problem did not go away. However, a jumper wire from the positive battery terminal to the electrical connection on the “fuel solenoid” at the injector pump seemed to get her working correctly.

Although working now, I believe the problem will reoccur. Here’s where I need your help. First, do I understand how the start/stop process works on my 4D61? Here’s my understanding. Turning the starter switch on activates an electromagnet on the “fuel solenoid” which opens the fuel flow to the injector pump. The glow plugs are activated separately. Turning off the starter switch deactivates the electromagnet on the solenoid to close the fuel supply, which stops the engine.

Do I understand the process correctly? Have I correctly zeroed in on the problem as being with the “fuel solenoid”? Or am I missing something? If the solenoid is sticking (both opening and closing), can I clean it out? How? Can I lubricate the inside of the solenoid to help? Don’t want to really screw-up this thing.

Thanks for your help.