Suburban Hot Water Heater Issue.

Ah shucks! Scrub ALL the advice above! Tell the wife it's now "toast" and you need to just get a new camper! :B If she believes it ... well ... think of the possibilities! ;)

No clue how to help you here, except to clean as folks indicated above.

Sooting will cause combustion chamber to get dirty
Mud dabbers/nests etc will cause flame to blowback out of combustion chamber
Yellow sooting flame is due to RICH Fuel/LEAN Air condition....dirty orifice/burner tube

Take the covers and burner tube off to expose both ends of the large (about 2 inch) tube that carries the flame through the water heater. It's just a big "U" tube that runs through the water and carries the products of combustion back out. It needs cleaning once it a while. The best way I know to do that is to run a rope through it so you can grab both ends. Take a shop towel type rag and tie it in the middle of the rope. Then drag it back and forth through the tube several times making sure it swabs the entire length of the tube. Then put it all back together and your nice blue flame should return. Wasps like to build nests in that tube and block the proper flow of gases. ANYTIME your water heater leaves a black streak up the side of your water heater, this is the thing to do to fix it.

Change the regulator

ORIFICE.......
It is dirty
Soak it in alcohol then air dry (no poking/no high pressure air)

Clean the burner tube using a small bottle brush


Propane flow/pressure pulls air in thru opening in burner tube right after orifice
Air mxiture is determined by propane flow

Propane flow....critical to proper air/fuel ratio for clean combustion BLUE Flame

I’d make sure there is no blockage in the intake tube, burner tube. There’s not really a lot of adjustments on a Surburban like there is on an Atwood.

I still go with a spider web. You need to pull the tube off so you can find the orifice. Do not poke anything through the hole in the orifice, but do firmly wipe it off with something. Then clean off everything downstream of the orifice. Find a way to push and pull a rag through all the chambers for the flame. After that put it back together and I'll bet it fires.

I've also read on here about some kind of oil that can pool in propane lines and cause problems. If cleaning doesn't help I would probably turn off the propane bottles and disconnect the propane line. Then open a bottle slowly to see if you have good gas flow.

Did you actually run a brush through the burner tube? It doesn’t take much at all to disrupt the gas flow.

I would be checking the air intake to make sure that nothing is blocking it. the yellow flame suggests to me that its low on oxygen. Just an idea.

It's one of two possible issues. You either have components that have gone bad or it's an adjustment that needs to be made. Here is a link to a video that shows how to adjust the air intake when you get too much yellow flame. Adjustment Video