350 Diesel

Have been working on a friends 350 Diesel. Have had head done and injectors checked. New main and Rod bearings. Timing has been check several times and is on. Valves set hot per spec. Starts and runs good to about 2/3 throttle then starts to sound like a skip.
When I took the injectors in I told them what the book called for and he said that didn't matter they go by the nozzle tip to set it.
Checked backlash on the pump drive to cam gear today and tightened up some but no change.
The owner had pump done some years ago with very little use after.
It seems to run better under load at full throttle. He didn't bring a drawbar for the two point hitch so all I can do is load it going up hill.
Someone told me maybe something sticking in the pump from lack of use and might just be better to run it. I'm wondering if anyone has had similar issues or ideas I might be overlooking.
Have video but can't post here.

Sounds like either the pump advance is not working right, or static timing needs advanced a bit. Might try advancing the timing some first and see if it helps. Which 350 is it, row crop or utility? Row crops had the high idle a bit lower than the utility models did.

It's a Utility. I did play with the timing while running and it just seemed to raise and lower the rpm's but the skip was still there. My friend has a lot of money in parts in this tractor so I really would like to get it running better for him. Thanks

Easy cheap stuff first. A good dose of fuel conditioner and work it.

I don't have the book on the 350 injection pump, but I do see it does indeed have the automatic advance on the parts picture. Does not look to be adjustable externally though like the 4 & 560'S are. You need to put the plastic timing window on that pump to see if it is advancing timing when running like it is supposed to. I would call a fuel shop and get the specifications as to how much and when it should advance. There are two kinds of advances , a load advance and speed advance. I would think an energy cell engine like that would be speed advance but that is just a guess. All the 460's & 560's etc used load advance but 706, 806 etc used speed advance. They work differently so you need to have specs to check properly.

They operate off of primary fuel pressure so with no adjustment of advance and you find advance to be less than specified , you may need to do some pressure adjustments, or at least testing.

Also, it takes as lot of movement of the pump static timing to equal what an automatic advance would do and it is never advisable to turn pump while engine is running as it could cause misalignment and wrap your hand into a pretzel.

I saw a lot of injection nozzles pulled and brought into me to repair when the problem was merely an adjustment of advance was needed.

You are right, 350 has speed advance. 460, 560, 660, some 656 had light load advance.

I ended up removing pump and taking to the diesel shop to check. Sounds like it's above my abilities. Thanks for the responses. I'll let you know what happens.