275 Valve Service
I was asked, by Andy, about covering the 275 valve. So, I put together this little piece. Here, I will be working on a spare valve, so it is not on a lantern, and therefore, there will be some necessary limitations. For example - I won't be able to show the adjustment of the packing. But, I will refer you to the above 275A tutorial for that procedure, since it is essentially the same thing. Also, I will not be installing any new parts - which, of course, you would be.
Since both adjusting the packing & adjusting the F/A tube require that the valve be fully assembled, I'm going to undertake these as two separate operations. First, I will deal with packing replacement.
OK - here are some views of the 275 valve:
As you can see, it is very similar to the 275A valve, with some differences. First, the 275 uses an external indexing system (the silver bracket wrapped around the valve). Also, this valve uses an F/A rod, in addition to the Schrader valve. Because of that, operationally, this valve has three positions - OFF, LIGHT, & ON. This differs from the 275A which has two positions - OFF & ON.
Let's get started. It is my understanding that most of these valves retain the Index Assembly with an "E-Clip". I'm not sure why, but this one uses a pin & washer to do this.
So, first, we punch out the pin (or remove the clip if you have that)...
and remove the washer.
Remove the index assembly.
Next we must remove the index spring. This is difficult to remove, and must be worked off the valve stem using pliers, as shown.
Loosen & remove the packing nut, counting the number of turns that it takes to remove it.
Pull out the valve stem with the old packing. This will take some work, and perhaps the application of some heat to accomplish.
These are all of the components of the stem. You can see some differences as compared with the 275A valve. This is because of the external index system, rather than the A's index washer. The primary differences to the 275A are:
1) There is no index washer &
2) Both packing glands are flat washers (no cupped washer on this one)
At this point, you'll want to clean the old packing and crud from inside the valve body, and from the valve stem. A small brass brush will take care of the valve body, and some #0000 steel wool for the stem. Remember to go lightly as we don't want to remove metal, just old packing & crud. When done, we can reassemble the valve:
Insert the valve stem into the valve body. Turn it back & forth, while moving the eccentric block up & down, in order to line up the notch in the block with the pin on the stem. You'll feel the pin drop into the notch. At this point, turning the stem back & forth will make the eccentric block move up & down, as it should.
Now place one of the packing gland washers over the stem and into the body.
Now comes the new packing...
followed by the other packing gland. Press in until it stops.
Thread on the packing nut.
Now here is where things get a bit difficult. Since this is a spare valve I'm working on, I can't show the process of actually setting the new packing. You can refer to the above 275A procedure, because you have to, basically, do exactly the same thing. The problem is, on this valve, you have the index assembly to deal with. To adjust the packing, you have to remove the index assembly every time you want to turn the packing nut. Here is what I would suggest. Turn in the packing nut to within 1/2 - 1/4 turn of the number of turns you counted when you removed it. For example, if it took 3-1/2 turns to remove it, then turn it in 3 turns. Put the knob on & turn the stem back & forth. Feel the tension (drag) on the shaft. If it turns too easily, go another 1/6 turn & try again. If it is hard to turn, back it off 1/6 turn. Continue until it feels about right. Now re-install the index spring onto the stem & push it all the way on until it stops, as shown:
At this point, I refer you to the 275A procedure for partially assembling the lantern to adjust the packing. The only thing is that, in order to light the lantern, you will have to temporarily install the index assembly & the knob...
so you can set the valve at the proper positions (OFF,LIGHT, ON), then remove it to inspect & adjust the packing. A much more difficult & tedious procedure than for the 275A. I'll repeat the warning about doing this:
*** IMPORTANT! - When doing this, you could possibly have raw fuel seeping or leaking out within a couple of inches from lit & flaming mantles! DO THIS AT YOUR OWN RISK! I am NOT responsible for any failure, injury or catastrophe of any kind resulting from this. If you can find a way to pressurize the packing without lighting the lantern, I advise that you do so! ***Once you have the packing adj
usted properly, replace the index assembly, followed by the washer.
Now, replace the pin and use the punch to insert it to the proper depth, as shown.
---------------------------------------At this point, we'll move on to the F/A tube. Unscrew it from the valve body.
Using a Schrader valve tool, unscrew the valve from the tube.
Now, remove the F/A rod & spring
The dismantled F/A tube:
Clean the F/A tube thoroughly. Pay particular attention to the smooth seat just below the threads, here, inside the tube. Tough to see in the photo. But it is very important that it be cleaned without scratching or gouging, as this is where the Schrader valve seats & seals against the tube. I usually use a combination of carb cleaner spray & scraping very lightly with a jeweler's screwdriver. Again be very gentle & do not scratch this surface!
This is the fuel pickup, at the other end of the F/A tube. It must also be cleaned. I usually spray carb cleaner through it, then ream it out gently with the F/A rod, and then spray carb cleaner again. Be careful not to bend the rod when you do this!
Clean the rod by brushing lightly with #0000 steel wool, then wipe with clean rag.
Place the spring on the rod, then insert the rod into the F/A tube.
Screw in the new Schrader valve & tighten it snugly with the tool.
Now, we'll adjust the F/A tube. Screw it into the valve body until you feel some resistance. You might want to use some threadlocker if the fit is loose. We need the tube to maintain its position, once adjusted.
Set the valve to the OFF position.
The rod should be blocking the orifice at the pickup. It might be flush with the orifice, or it may protrude a bit, as shown. As long as the orifice is blocked, that's fine.
Now, place your mouth over the generator outlet and draw a suction. Turn the F/A tube in until you are able to suck air through. Then, slowly and carefully back the F/A tube out
just to the point where you can no longer suck air. Then back the tube out further - another 3/8 turn. Verify that you can
NOT suck air through the valve.
Turn the knob to the straight up position, and the eccentric block should be at its highest point.
Turn the knob to the first detent, as shown. This is the LIGHT position.
Using your mouth, draw a suction as before. Now, you
should be able to suck air thru the valve. The rod should still be blocking the pickup orifice as shown.
Now, turn the knob fully to the left until it stops.
This is the ON position. You should still be able to suck air, and the bottom of the F/A tube should look like this:
You can see that the stepped (small diameter) portion of the rod is in the orifice, which will allow full fuel flow through it.
This should be straightforward. However, I'll just say - if, when following the above procedure, you can suck air when you shouldn't be able to, then turn the tube back out (CCW) a small fraction of a turn & try again. If you can't suck air when you should be able to, turn the tube in (CW) a small amount! Then go back & re-check all positions, making sure all conditions are met.
Good Luck,
BobA
![[016]](http://i953.photobucket.com/albums/ae20/boba61/Coleman%20275A%20Lantern/Packing%20Replacement/016.jpg)
![[biggrin]](http://cdn.websitetoolbox.com/images/boards/smilies/biggrin.gif "Big Grin - :D")
![[absolutely]](http://img.photobucket.com/albums/v300/Murff/Emoticons/absolutely.gif "Oh Yes - :Oh Yes:")
- Andy