LDS-465-1A Drivability. Will not idle.

[Recovry4x4]

So, I have this M51A2 with the LDS. It had sat for some time so when I got it, it was not running. Prior to it's slumber, it was a dependable runner.

I found that the fuel shutoff rod was frozen in the pump. I pulled it out, took it apart and freed it up. Put it all back together and viola, she starts up pretty easily. Keeping it running was another issue, it just dropped off under 1000 RPM.

Since then I've replaced the fuel tank, completely cleaned and flushed the in tank pump which is running. Replaced all 3 fuel filters and made several attempts to combat the problem with idle screw adjustments. The fuel is fresh, purchased it today. Nothing has worked so far.

Today I ran it for quite a while hoping maybe a heat/ cool cycle might make a difference. I've not fooled with fuel rate at all. I know there are more adjustments such as the droop screw but I don't want to fool with things I'm not yet familiar with. I do not think the FDC has been bypassed and I have no idea if it may play a part in this. If anyone has any ideas, I'd sure appreciate it.

 

[NDT]

I had the opposite problem, LDT wouldn’t come off idle. Beating on the injection pump fixed it. As low tech as it gets.,

 

[Ferroequinologist]

Sounds like the gov is sticky. The one in the LDS I put in the m109 did that, still will on occasion not idle under 1000rpm. Took the FDC off and just kept hosing everything down with kroil and working the linkage. It runs amazing otherwise, but will hunt like crazy till it warms up most of the time. I have two spare pumps been meaning to go through one and swap it. Just haven't had time.

 

[Recovry4x4]

Is the governor side of the IP engine oil lubed? Oil really needs changed.

 

[Ferroequinologist]

Yes, engine oil lubricated, and at the back of the IP as well.

 

[Recovry4x4]

Sitting here trying to digest TM 9-2910-226-34. its a rough read for an old guy.

 

[Recovry4x4]

Another question that I can't seem to find the answer, can the FDC be removed and reinstalled without too much fuss? The fuel rate screw seems to be a part of it.

 

[Recovry4x4]

Update. I've been driving this thing around the church lot here and there. It's been through a couple of heat/cool cycles so far. I was hoping that whatever was sticking in the governor would work it's way loose. After one of my 5 minute rides this morning, I backed into it's parking spot and stopped feathering the peddle. It stayed running. Wicked the throttle a few times and each time it settled into a nice smooth idle. My next step will be changing the oil. I was contemplating a way to flush it out just a little. Was thinking of draining off a gallon of oil, adding a gallon of ATF and warming it up. Any thoughts on this? I'd do it with fresh oil and filters but we would be talking about an extra 6 gallons and 2 more filters.

 

[Ferroequinologist]

I'd put half a gallon of marvel in the fresh oil and run that for awhile. Won't hurt the engine for that much to stay in there, and will help decrud stuff.

Or drain off a gallon and add a fuel gallon of marvel, and drive that some.