What is causing this to happen?

[Okrafarmer]

I know I've had that happen a good bit in SYP. Usually just milling along and WHOOPS there she goes. Less that 1% of the time. Some logs just get ornery. "Onnery" as the locals say.

[kelLOGg]

clintnelms, it is not clear from your pic if you use a filter in the diesel drip line. I use in-line filters to trap rust, sediment, etc. My diesel tank is part of the steel frame of the sawhead and that is the source of the rust. (It sorta surprises me that there is rust in a diesel-filled tank but there is.) I am on my 3rd filter in 14 years. They are very small. Hope this helps.
Bob

[btulloh]

Gravity feed is inherently inconsistent with this setup - that's why they use pressurized systems on more expensive mills.  The pressure changes constantly as the volume of water in the tank decreases, among other things.

One thing that would help is to move the flow control down closer to the bottom of the line.  When water enters the line at the top one drop at a time it does not create a consistent flow in the tubing.  If the tubing were full and the rate adjusted at the bottom it would help.  I've been meaning to make this mod myself, but so far I just put up with it.

[clintnelms]

Gravity feed is inherently inconsistent with this setup - that's why they use pressurized systems on more expensive mills.  The pressure changes constantly as the volume of water in the tank decreases, among other things.

One thing that would help is to move the flow control down closer to the bottom of the line.  When water enters the line at the top one drop at a time it does not create a consistent flow in the tubing.  If the tubing were full and the rate adjusted at the bottom it would help.  I've been meaning to make this mod myself, but so far I just put up with it.

That's a good point. Makes a lot of sense. Moving the flow valve down would probably make a big difference. If I open up the flow valve all the way so the tube between it and the shutoff valve is full then back it down to a drip it works fine for a while until air is in the line again. I see what your saying. Moving the flow valve would keep the fluid in the line all the way down to it.

[clintnelms]

The easiest thing would probably just be to get one of those sight glass needle valves and splice it in the line after the shut off valve. Then just leave the flow valve already on it at the tank all the way open and just adjust the needle valve for the drip.

[Ox]

Bingo. 

[Chuck White]

I had a PM suggesting I shorten the hose to fix a gravity problem that might be causing a problem with the drip rate. I did that and thought it might have fixed it, but I still think there is a gravity issue. I don't think the tank is high enough. After a little while I start getting air in the line and lose the gravity flow.

If you look at the picture you'll see that the shutoff valve and flow adjustment are almost parallel to each other. I can't really raise the tank that easy, so I think I'm going to have to grind the weld off on the bracket holding the cutoff valve and lower it and reweld it.

I don't think buying that $50 needle valve would fix the problem without still fixing the height of the shutoff valve first.

I think you're right Clint, there needs to be more drop between the two!

Before you cut and reweld, disconnect the line and lower the valve temporarily to see if there's a difference, then if it works, do your cut and reweld!

[ChugiakTinkerer]

That's probably why they moved the valve lower on the HM130.  I don't have any nice pictures, but here's one from Roundhouse's nice write-up on his.  The valve is on the right side of the green face plate with the logo.

[clintnelms]

Yeah there's several upgrades I've noticed on the HM130. I started to wait for it to come out before I got mine, but at the time I didn't know how long it'd be and I didn't have the patience to wait. 😕