I have a Suburban NT-20SEQ furnace in my 2012 Pod 177 and except for the approx 2-3" high yellow flame, runs well (I've just bought the pod). I only have limited experience with a furnace (in a previous pup but don't thing the flame was like this.

What I've done:

Would you be so kind as to review the 3 attached photos and pass along suggestions or just confirm the pics look normal? Maybe what I have is normal for this furnace???

Pics:

You have done everything right as far as I know yet when I look at my flame there is a tint of yellow but the flame is mainly blue. 

The only additional item I can add with my limited knowledge is to check both your regulator and the hose that goes from the regulator and screws into the propane line in the front of your 177.  I have a 2011 177 so we have the same setup.  What I found out (I had a problem with yellow flame on my fridge and HW heater) was a lack of oxygen.  When I took the regulator off a thick black gooey substance came out, the hose leaving the regulator had the same thing come out of it.  At the time my 177 was 9 years old.  For a total of $25 I purchased a new regulator and got a hose made at a local propane business that sells bulk propane to homeowners.  Took care of the yellow flame problem for me.

So I went and unscrewed the hose from the output side of my regulator and a yellowish liquid spurted out...probably an ounce or so (although liquid looks like its twice the volume when it spills to ground LOL)

I then removed the hose from the input side of the reg. The hose ends themselves look fine. So I think I'll look for a supplier for the regulator first.

So it's safe to assume the *no* liquid should ever spurt out of a regulator?....

Right.  I don't know of a way to properly clean out a regulator once that gunk is inside without doing more harm than good.  Anyway, I got a two-stage regulator off EBay with free shipping for around $ 18  two years ago. 

I was told by those 'in the know' that I should turn off my gas and open the line when not using for a month or more so this doesn't occur.  Seeing that this was never done in the first 9 years of ownership I guess it held up pretty well.

Here's a pic of the flame from the same basic angle for comparison purposes:

Originally posted by GlueGuy A yellow flame indicates not enough oxygen, or too much fuel. I would check air inlets and/or see if there is a way to turn down the fuel.

Is it possible GG that there may still be gunk or a pinched line somewhere that would cause this?  I had the same issue when I found out my regulator and propane line had the black gooey substance, once replaced the flame was nearly totally blue.

I agree, yellow indicates lack of oxygen and since the OP still has this issue, especially seeing that he has this problem with the HW flame which is in the open tells me that another line is pinched or there is yet another line that needs to be cleaned out or replaced.

If yellow flame is indicative  of low oxygen, then check the outside air intake for mud daubbers or other insect  nests. In our area, they are quite invasive and all of our vents have to be covered with insect screening. they can definitely stop up pipes, inlets, openings, etc.

Vann

I suppose that is possible, but the gunk would theoretically be restricting fuel flow and/or contaminating the fuel on its way to the burner. I don't know how long that might last. If you can't find some blockage in the air supply, it would probably be worth a try to blow the line out with compressed air.