Optimus 155 dismantling/reassembly

Got to grips with the twin-burner kerosene boat stove classic. It’s best to get the working parts - tank, burners, quick-lighters, out of the stove frame.

The burners, tank fuel filler riser nut and the stainless steel sub-assembly frame on which the quick-lighters are mounted are all that hold the components below in the frame. The pump has to be removed to enable the pump tube to slide out of the front mounting hole in the stove frame.




Opportunity to clean the rest of the stove frame, gimbal components, pan clamps.




Loosely assembled to illustrate how the working components go together.










The O-ring in one of the quicklighters was no longer sealing so disassembly of both was called for to replace each one.




@Afterburner and @pau-i-amor have posted good work on these stoves, so this is something of a recap of their observations.

Those articulated control arms projecting through the front panel turn each quicklighter jet on the body component, a left-hand thread on the right-side quicklighter ...




a right-hand thread on the one on the left.




Let to right: quicklighter shroud (screws onto the jet component to the right of it); the articulated control arm (clamped to the jet with an Allen-key socket grub screw); the quicklighter body with O-ring seal; the feed pipe comprising two concentric tubes (fuel in the centre tube, compressed air from the top of the tank in the outer tube).




One of the quicklighter fuel/air supply pipes.




Gauze strainer on the fuel pickup.




The jet.








The quicklighter is closed when the conical tip of the body (below) is torqued down on the recessed mating surface visible in that last photo of the jet. The fuel feed hole is visible towards the tip.




The air feed hole is visible (below) at the top of the air passage groove cut across the threads the jet pivots on. The combination of pressurised air and fuel and a very fine jet orifice results in atomisation of the fuel and clean (non-sooty) and hot burning to get the main burner up to vapourisation temperature.




The pump is of the O-ring type. On the push stroke the O-ring ‘rides’ up the taper of the piston seat, expanding the pump bore to create a better seal. On the ‘pull’ stroke air gets past the piston, ready to be compressed on the next push.






Pump end cap incorporates a locking arrangement reminiscent of that on a Petromax lantern.






The long pump tube calls for a correspondingly long non-return valve removal tool. I made one up by grinding hexagon flats on the end of a standard NRV tool, then connecting that up to a small ratchet and extension bar.




It should be possible to unscrew the pump tube at the tank to get access to the NRV but getting sufficient grip on the tube to unscrew it without crushing it prompted the solution I chose.




Copper burner cones. I agree with Afterburner, new cones aren’t called for to ensure a seal on removal/replacement of a burner, but I took the precaution of annealing the cones by heating them to a dull red and allowing them to cool.










Reassembly. I’ve removed the quicklighter shrouds, installed when the sub assembly pictured is in place in the frame top deck. Burners removed, pump removed.








Tank fuel riser screw is in place.




Pump reinstalled.




Screws fixing the quicklighter mounting frames to the top deck are replaced.




Control arms for the quicklighters are installed, adjusted so that when the quicklighters are shut off there’s some clearance between the control rod and the base of the slot.









Finally, quicklighter shrouds installed, then the burners.




John

 

Complete fettle.

Here is my QL fettle post: https://classiccampstoves.com/threads/optimus-quick-lighters-pre-heaters-in-155.28489/

 

Hi John @presscall Great post as always. You have a rare talent in your ability to breakdown, restore and re-assemble classic stoves whilst photographing, and describing the whole process in detail.

Best Regards,
Kerophiee.

 

Very visual and detailed, nothing left in shadow.
Really rare talent. Thank you very much!

 

Thanks!

Reassembled, time to test my new (to me) stove. It was an eBay purchase, the seller within easy driving distance and he accepted my offer price of £50, a bargain.

Something I couldn’t have anticipated, a pinhole in a brazed joint on one of the burners. Still a bargain purchase, with a straighforward repair in prospect, one I’ve had to carry out on burners before.






I cleaned up the area around the pinhole.




With experience of repairing burners before as I said, I was aware that a MAPP torch requires some assistance. The heat-soak effect of the bulk of metal in a burner can leach away the intense but narrow heat of the torch. Better to help out the torch with a large kerosene blowtorch, set up in this way to get the whole of the burner up to red heat (jet, spindle, pricker needle removed to let the heat flow without hindrance through the burner).




Localised intense heat was applied with the MAPP torch at the same time, sufficient to melt and cause to flow the flux and silbraze I’d applied.




Cleaned of flux residue and ready to reinstall in the stove.




Repair done, time for a brew.










John

 

Having removed and replaced a burner a few times during the pinhole leak repair process, the copper cone developed an annular groove which with further removal/refitting would get deeper and I could visualise the cone sinking further and further into the burner.

In anticipation of the day that happens (no time soon) I got some spare cones in stock to keep with the stove. £4.99 for five. Aluminium now.

 

Hi John, I know this is an old topic, but very actual for me now. I just began dismantling my 155 and I wonder, unscrewing the burners is it done from the top with a wrench?
I think it is a bit hard to reach.
I already know I need at least one fuel pipe to one of the quick lighters but looks like I can buy them here in Holland.
I suppose they are very hard to fix, fettle.

Thanks so far, regards,

Ton.

 

@ton visser
Hi Ton!
The bottom burner nut is loosened (easy access below the stove top plate) with a wrench to break the seal and once the larger nut clamping the burner in position on the top plate is undone (and holding the pipe elbow fitting nut in the wrench) the burner is unscrewed and removed by hand. The sealing arrangement is the equivalent of what we call in the UK a compression pipe fitting but using a soft metal (copper, later replacements aluminium) seal instead of an ‘olive’.

The burner/lower nut/‘cone’ seal and fuel feed pipe arrangement.



I’d recommend annealing the burner sealing ‘cone’ washer (get it to red heat, let cool) before reassembly, or as I did buy some replacement cone washers (aluminium) from Base Camp. Re-using the old washer is fine unless it’s damaged.

John

 

Hi John, I managed to unscrew everything. Unscrewing the burners seemed much easier as on ordinary stoves, they can be much harder to loose sometimes.
The cone washers I found were aluminium so one can assume there has been some fixing after new.
Om my 155 the hole pump pipe came from the tank, does not matter, everything must be checked.
I had to fix a thin 14mm spanner to loosen the two Quick Lighters so now everything is apart.
About the QL I have some questions, first one about one of the copper pipes. I found some soldering on one of them, I suppose they are hard to handle?
I will try to take away most of the soldering with a small steel brush on a Dremel, after that fix the pipe in a right position and fill with a very pure petrol we call it wasbenzine in Holland, the goal is if there is some sort of crack the fuel should come through.
We do the same with car motor cilinderhead valves after renovation, to check if the valves are tight.



Then about the QS burners, I found two sorts of, one with a thick body and one with a thin body. The rest of the dimensions are the same.
Likewise the tread to screw them on. I have looked on one of my lamps, Optimus 1550 with a QS it has the same part the flame is coming out, mind you, the one with the thin body.
I suppose they are all interchangeable.
See on the pictures yourself.





Have a nice Sunday,

Ton.

 

That annealing by the way John, I suppose one cannot do that with the aluminium cones?
Are those reusable?

Ton.

 

Aluminium can be annealed but (i) there’s probably no need in this application (ii) it’d be tricky getting the aluminium to annealing temperature without going a bit over and melting it.
Regarding the quicklighters, those on mine are identical but the difference between your two seems superficial and they’re evidently interchangeable, so not a problem I guess.
I’d not bother too much about the neatness of the soldering of the pipework if it doesn’t leak. Interesting your use of ‘white’ gasoline to seek out a leak.

John

 

About the pipe John, it leaks, that was to be expected, someone made some effort to mend it before.
I am not good in soldering, but working things out I can manage.
I thought about the next solution: a plastic hose over the cone on the QL side, put the complete pipe in some water end blow, you should see two traces of bubbles on the other side of the pipe, on e from the inner and one from the outer one.
In my case I have tree traces of bubbles, in the elbow.



As I said, I am not that good in soldering but I have a friend who is a master in it, 30 km away, no problem.
I will give him a call tomorrow and hope to be back here as soon as possible.

One more question, do you happen to know someone on the forum who has been working on those 155 QL pipes, especially removing them from the tank?

Regards,

Ton.

 

??? You’ve successfully removed yours from the tank Ton. I’m not sure what you want to know.

John

 

No, there is a reason I am asking John , the first pipe I removed was the one that leaks. After that I tried to remove the second one and exprianced some sort of obstruction inside the tank. It was not simple to get it out. And I wonder if anyone recognized this problem.

Regards,

Ton.

 

@ton visser
Ah, I see.
Yes, I recall one of the quicklighter fuel feed pipes on mine resisting removal. The threaded connector unscrewed and detached easily enough but the clearance between the fuel strainer on the end of the pipe in the tank and the access hole is very fine.
I rotated the pipe - clockwise-anticlockwise-clocwise and so on - while gently pulling the riser tube perpendicularly to the tank. A squirt of releasing oil helps. Gently does it!

John

 

Yes John, that is what I mean. But the hole is the same size. Looks like there is something in the way on just that side. Good to know I am not the only one who has experience with that.

Regards,

Ton.

 

I`ve got one of these cookers but when I got it the quick lighter tubes were badly burnt . So I had to turn the quick lighters off and start it with meths . It does loose pressure over about an hour . Thanks for showing your strip down I`m going to have a play but going to try and not disturb too much if I don`t have to .

 

Question is how did you turn the quick lighters off? Just not using them does not mean they cannot leak, I had a leak in one of the quick lighter pipes near the tank.
Find out where your stove leaks first.

Ton.

 

All I did was to unscrew the grub screw on the quicklighter handles and then turn the jets so they were fully locked down and then re tighten the handles at the top of the slots so that they could not be used but I had no leaks in my pipes .

 

Sorry, I don't have the answer but the same problem, can't get either out. Frustrated for days, is there a solution? This was for Ton Visser's problem.