Elementary question: How to remove a burner from Optimus 157?

https://classiccampstoves.com/threads/fitting-replacement-parts-on-regulated-burners.8843/

 

Actually, this happened not with the decoked burner but a brand-new one which previously had never seen fire.

I had to read up on the 'click' thing. I hadn't even thought about this, that some adjustment might be needed for the little teeth on the pricker support. Now I see what could go wrong. Somewhere on this site I found a step-by-step description of what to do, written by Tony Press, which I intend to follow. I guess I will do some experimenting with the old burner (the now-decoked one) in my basement, like trying to count the clicks, before heading to the freezing boat again.

Will let y'all know how that turned out!

 

@kerophile : Just found the link. Looks great!

Thank you!

 

OK, the weekend is over so I have an update

I practiced the '3-5 clicks' settings procedure on the old ("de-coked") burner at home since I had never done that before. Seemed pretty obvious once I did it a couple times but of course this was only a dry run (literally), it was only on the burner sitting on my bench without being connected to a stove.

So today I went to the boat and repeated the process there. Everything went as expected, I set it to 3 clicks and fired up the stove. Result: A beautiful blue flame (and no leaks!) but the burner still does not get as powerful as the old one used to, and as the second burner does. In other words, unchanged from last week's result.

So, I figured I was at the wrong range of the '3-5 clicks' range and I went to the other. So I put it to 5 clicks. Result: The same.

This was unexpected. Is it possible that this burner for some reason only can do 'low power?'

Since the stove is at least now usable, I closed it up and put it into its gimbals (I had it sitting on the salon floor, and before in the cockpit, for testing). But if someone has a suggestion that allows the burner to reach its full potential and which, if at all possible does not require taking off the burner again, I would love to hear about it.

Thanks!

 

This is purely gut feeling but your original may have a slightly enlarged jet giving more fuel and slightly greater output.

It's quite marked the difference a brand new jet does to perceived output.

 

I did not know that this can make a difference but it makes sense. It is certainly easy to swap in the old jet. However, I don't think that is the reason because the very first thing I did when I started fiddling (fettling?) with the old burner was to change the jet to a new one. Precisely because it is so easy to do. It did not make a difference.

One thing I forgot to mention when I described the symptoms: When I turn the knob clockwise, the flame gets smaller until eventually it dies, of course, because the spindle cuts off the fuel. When I turn it counterclockwise from a low position, the flame first increases, then stays constant for some time, and then it goes down again (did not test if it completely dies). Is that normal? Is that because the cleaning needle blocks the jet?

 

Hi @OldMariner Have a look through this thread which shows a cut-away burner:

https://classiccampstoves.com/threads/regulated-burner-cutaway.15697/

The regulated burner depends on the simultaneous movement of a needle valve and a jet cleaning needle mounted on a toothed rack.

With the regulator knob fully clockwise the needle valve is fully closed and the cleaning needle at the bottom of its travel. As you turn the knob counter clockwise the needle valve opens, increasing fuel flow and burner power. The cleaning needle also starts to rise.

Eventually the regulator fully raises the cleaning needle, until it fills the jet aperture, and can extinguish the flame.

Maximum power occurs approximately half way between the needle valve being fully closed and cleaning needle fully raised.

The total range of control knob movement is only 1/3 to 1/2 revolution max.

You asked about any checks you can do in-situ:

If you want to see the maximum amount of fuel coming out of each burner, forget the matches:

1. Pump up the tank.

2. Take off the outer burner caps.

3. Open the two burner valves to maximum and compare the shape and height of liquid kerosene column for each burner.

4. Any difference might be due to jet aperture size or possible burner/piping part- blockage.

Best Regards,
Kerophile.

 

have not forgotten this ... crazy work schedule ... will come back to this as soon as I can

 

OK, this weekend (yesterday) I could steal a couple hours and check on the situation. I did what you suggested: pumped up the pressure, took off the caps, turned the knob of one burner and ...

WHOOAAAA!!! Kerosene shot up at least 3 feet, maybe 4, hitting the ceiling (of the boat)!!!! I had no idea there was that much pressure!

After I cleaned up the mess, I released the pressure and pumped it up again, but only 5 strokes, instead of the 20 or so that I usually apply. Even with that the two jets were over a foot high, maybe a foot and a half. I suppose it is good news that they looks both very similar. So I guess we can exclude any problems with the plumbing.

My newest idea is that perhaps the caps are different? Maybe there are small differences in the size of the orifices of the outer cap?

But anyway, this brings up another question: I wonder whether I am applying WAY too much pressure. Honestly, I never thought about it, nobody taught me how to use this thing. There is a pressure gauge on the filler cap but it is broken (I tried to find a replacement but no luck; if anyone knows where this can be had I would be all ears). So, what is the received wisdom on how much to pump it up? It turned out that when I pumped up only 5 or 6 strokes, the stove burned quite well. Should I do that, instead of the twenty that I used to apply?

Thanks as always!

 

@OldMariner

If your flamelets start to separate from the burner and dance around, rather than keep a nice pattern at the holes, you have too much pressure.

Cheers

Tony

 

Hi, now we know that fuel supply to the two burners seems to be similar and adequate. Good.

Now you should swap caps between the two burners to see whether the poor flame performance moves with the caps or stays with a particular burner.

You should also be aware that tanks on kerosene pressure stoves should never be filled more than 3/4 of capacity. The air space plays a critical role in the pressurisation process.

Regards,
Kerophile.

 

As always 'it depends' is general advice on number of pump strokes. It's quite a variable and you are the expert on your particular situation.

With a full (3/4) tank and a pump in perfect working order then my gut feeling would be 20 strokes is probably max. It's whatever you find works in your situation.

I have an Optimus 00 with a worn jet that I wouldn't take beyond 5 - 6 strokes as it gets a little over excited, a new nipple and it would probably take a lot.more, but I"m not too worried about timing things so long as I get a cup of tea out of it.

 

No flamelets, so I guess the pressure was not too high.

Thanks!

 

Yes, I will swap the caps next time I am on the boat and see what happens.

Thanks for the tip with the tank capacity. I did not know that. Not that it is a problem currently since when I took off the burners, most of the kerosene drained out of the tank (another mess to clean up)

 

I never had a problem but I think in the future I will be a bit more conservative and see how the stove does with less strokes. Just to save wear and tear and pump and valves.

 

Sorry for not replying earlier. Work has just been crazy the last month. Should be better now.

I did manage to sneak up to the boat and play with the stove two weeks ago but did not have the time to upload the pictures and reply here. I swapped the caps and the result was basically nil. The left (brand new) burner still does not seem to have as much dynamic range as the old one, even after I changed the caps. At this point I am willing to leave this as one of the unsolved mysteries of the universe, right up there with the question 'what is dark matter?' and the grand unification of all fundamental forces. For my purposes, the stove is perfectly usable even if I have a little less control on one of the burners than on the other. The most important is that I can go sailing again and have fried spam for dinner, rather than cold spam!

One thing I noticed is that the 'inner caps' (I am sure there is a proper name for them) are of a quite different shape. One has holes at the top, the other does not, see the attached picture. Does not seem to make a difference though.

Also, for the record, the other picture shows both burner flaming away. The flame of the left burner(brand new, less dynamic range) has an orange tint to it. No idea why. But I guess this is as far as I can go with this. I am a happy boater now!

 

Hi, the flame pattern looks excellent on both burners and would certainly be acceptable to me. Use your classic stove and enjoy it.

You asked about holes on top of one of the inner caps :

“However, you will also note from the photos that there are some other small differences, for example, the inner silent cap the Primus regulated burner has holes on top.There are also holes in the centre up-stand of the corresponding silent burner body.
I believe this to be subject of a Primus patent, claimed to prevent or reduce the incidence of under-burn.

These perforated inner caps also turn up on certain conventional, non-regulated, silent burners. I have found that the burner operates with un-perforated caps just as well, so perhaps they are not critical in normal operation”

From this old thread:

Regulated Burners I have known.


Best Regards,
Kerophile.

 

Thank you, and everybody on this very helpful and friendly list, for their help!