OK, long post but bear with me.
I have the above unit and it worked ok in warm weather when new, blanketed it was ok in cold weather if you kept an eye on it, played with the flame and protected it from wind. This ain't no high end smoker. Anyway... I go to use it 2 weeks ago and have a large yellow flame, the shut off valve won't shut off, there was also flame coming out of the venturi area. To check every thing out you have to remove the front legs, and dismantle the burner unit, completly.
This is what I found. The valve was shot, there was a small leak in the swivel fitting that goes into the valve body, and spider webs in the venturi tube close to the burner. You can only really check the tube if you remove the burner from the tube, there are two small screws that mount the burner to the tube flange. This was causing a reduction in air and causing a back pressure that caused flame to come out of the venturi end of the tube which could cause the regulater hose to melt.
The valve itself looks like a Sunbeam grill valve (left) ? I think) from pictures I saw on a online grill replacement parts page. The valve was listed for $18. Instead, I found a ball valve with 3/8" hose barbs at Lowes for $6, cut the regulator hose and installed inline, so it is now the shut off valve, and the old valve was reinstalled and only controls the flame height, the other end of the regulator hose which swiveled on the old valve body and leaked, was cut off and reinstalled on the 90 degree 1/8 pipe fitting barb, after the old brass crimp was removed.
Now after leak checks and putting everything back together, the unit is working good. While I was at it, I cut 1/2" off the back of the water pan to let more heat by, put 2 bricks in the water pan with a cheapie 10" cake pan on top to catch drippings. The chip pan is warped but if you notch out the corners it could probably be straightened, I didn't bother, and I also don't use the pan cover.
So... it was a PITA, but it's working, for now, probably should remove the venturi tube and burner assembly once a year at least, to check that alls clear, and don't put in 2 racks of ribs before checking that everything still works, . Lucky for me I was able to adapt the propane grill to serve as an acceptable substitute. Cheers, P.S. the ribs were great.