Juki DDL-8700 Oil Pump System Clogged

[friquant]

How to unclog the oil system on this cloned Juki DDL-8700? 

This is the first pumped sewing machine I've worked on. Machine has been sitting for about five years. Actual model number is FEIT DCL-8500N.

Pump

The oil pump appears intact. At low speed (200 rpm) it appeared to not pump at all, so I disconnected the vertical output pipe at the top and kept increasing the speed until around 1700rpm oil started spewing out the top of the vertical pipe. So there's at least oil now on the upper hook bevel gears.

 

Splash Test

But there's another tube that feeds the hook, and I'm not seeing any evidence of oil near the hook yet. In this video the man does a splash test with a paper towel to check how much oil is reaching the hook: 

https://www.youtube.com/watch?v=hQCUZs1-vUY&t=163s

 

Here is my paper towel, still dry:

 

Valves

I have opened the valve that regulates oil to the hook:

and also opened the valve that regulates the oil to the needle bar crank assembly:

but still not seeing any on the hook or on the needle bar crank assembly.

Tthe user manual says that when machine is new or anytime after it's been sitting idle for a long while to run the machine at 3000rpm for a period of 10 minutes. So far I've run the head unit a couple minutes at 2400rpm (checked with tach). I want to see evidence of oil flowing before I run it enough that it really needs oil, if you catch my 22.

 

Filter?

Earlier in this same video the man cleans out the filter in the pipe behind the hook: 

https://www.youtube.com/watch?v=hQCUZs1-vUY&t=59s

so perhaps that will be my next move. As for the needle bar crank, I'm not sure sure what to disassemble to clear the way.

Water

Worth noting perhaps that I did find evidence of water in this machine. The oil pan drain plug is rusted in place and I did not manage to free it. Not even with mild application of a kitchen torch, a few hours soaking in diesel, and an impact driver. 🤷‍♀️ Also the old oil looked milky. And in part of the presser bar I found a couple drops of water concealed within some drops of oil. But I don't really expect water in the past to clog the oil pathways

Manual

I'm using this as a manual: https://www.juki.co.jp/industrial_j/download_j/manual_j/ddl8700/menu/ddl8700/pdf/instruction_eg.pdf