Hi all, This is my first post here but I've been lurking around a while to learn the ropes of fixing my first stove. I previously revived an old Tilley X246 lantern I picked up at a bootsale, but that is my only experience in this field and it was a while ago! What I have is a good old Primus 96 (date code AA, which I believe is for 1936). It is complete apart from the fuel bottle and I believe a spanner that should also have been present. The all important bit of brass gauze inside the burner seemed to be present and correct. I have tested the stove and it does fire up but there are clearly leaks somewhere as the base was soon dripping with fuel. I ordered a Juliands repair kit from eBay and have already removed the original lead burner washer and the rubber tank lid washer - the rubber washer was perished and hard, so probably wasn't making a good seal. Before I go any further, I'd be grateful for some advice on a few points where I'm unsure: 1) The leather cup washer for the pump which came with the kit seems much too large for the pump tube. Is this normal, and if so, how do I make it fit? 2) Regarding the lead burner washer, what is the best practice when installing this and when adding/removing the burner in the course of using the stove? Since the lead will not spring back into shape, unlike rubber, does this mean the burner will need to be screwed on slightly tighter each time it is used to make a good seal, eventually over-compressing the washer and requiring another replacement? 3) I haven't done any investigation of the NRV and am hopeful it might be ok. Is there a particular test I could do though that would shed light on whether it is healthy? Thanks for reading. I will add some pictures later. Kind regards, Liam
Hello and welcome! If it is much too large, you may have been supplied with a pump leather for larger, 2-pint stoves. Just insert in place and tighten the vapouriser tube to seal. It should last a good few years of use before needing replacement again... Empty tank, fit reserve cap, pump up pressure, immerse tank in water. Look for escaping bubbles. Let us know how you get on!
+1 Or…Leave in freezer for 10 minutes or so, tighten fuel cap with new washer, hold thumb over burner bung or if burner left in place, finger over burner orifice, dunk in hot water. Fount emptied of fuel of course. Pump shaft can be removed also to check for air bubbles there too in the pump tube/NRV sealing. I don’t travel with fuel in the fount, so I don’t worry about the reserve/travel cap sealing. I usually look for leaks by the lead seal as the burner needs to be pretty snug, have also seen many times where a second lead or ? washer was added which does not seal. Duane
Yes, excellent advice- always remove all traces of previous material before fitting a new lead washer.
Thanks all, that's very useful. I've now fitted the lead washer and tried dunking it in water while pressurised with air with the burner blanking cap fitted. I can see some bubbles escaping slowly around the burner cap, probably because I don't have it tightened down enough (I don't have a tool that fits the slot exactly and didn't want to damage it). I think I managed to suck in some water by mistake, so I'll let it dry out before test firing with the burner fitted. In the meantime I'll look for a suitable spanner to properly tighten the burner. Here are a few photos. I've included one of the replacement pump cup I received, which definitely looks like it might not be the correct part. I've also attached a photo of the existing pump cup - is there a way to tell whether it is in need of replacing? It seems to fit nice and snugly in the pump tube but I've nothing to compare against at the moment! Cheers, Liam
@Voxophone The cup on the rod pictured actually looks good from what I can see. My maintenance would be to soak it in oil (I use neatsfoot because it is supposed not to harm leather). Leave it to have a good soak, perhaps overnight. Then the leather should be a bit more lively and you can massage it and tease the leading edge out a bit so as to get the best seal. With a little more oil on it, fit it in the tube and see how it feels. If you get incredible resistance, then your NRV is stuck shut! - you can gently prod it with a piece of wire in the centre hole. From your picture, the pump cup appears to be the correct size for your stove. If you are having issues with it, you might like to try the method that I wrote about here. Basically oiing it, fitting it to the rod easy end first (like your picture) and forming it in the tube, then carefully refit it to the pump rod the correct way round and it should then be easier to fit in the tube. Good luck! Crossed with HikerDuane below
These can be a bear to insert the pump back in. Old cup looks good, massage oil into it and spread it lightly so it makes more of a tight fit. I use a dental pick to push the cup edges into the tube, or roll up a bit of thin metal sheeting to act as a cone to ease inserting the pump back in. Duane
I cut a drink can to have a 'sheet'. Roll it like a funnel to push a tight cup into the tube. No damage to the cup.
I've run it with fuel now. No leaks, but I think it's safe to say my technique needs improvement... I managed to cause a huge spout of burning paraffin up the jet, setting the whole top part ablaze After cleaning up that mess, with a bit of spluttering and some green flame it did settle down. Below is the steady flame I got. The spreader seems to be getting very hot and glowing.
Needs a good preheat, screw in air screw before preheat fuel burns off and add pressure just before preheat flame goes out, add more pressure after 20 seconds or longer if cold out or windy. May take a few tries to get your technique down. Looks good. Plus, be sure mesh in burner is up in the tube all the way, may make the difference at times. Duane
Yes, the cast iron burner plates do glow red. Perfectly normal. Looks like a really nice set and a none too traumatic fettle. Well done!
To add to others comments, there is a lot of mass to heat in the vapouriser tube, burner bell and flame spreader plate, and only a small spirit cup on these stoves, so priming can be marginal, especially outside with even the slightest breeze. The windshield helps, but an evening bigger improvement indoors or out is a piece of carbon felt placed in the spirit cup, which reduces boiling of the meths and gives a longer prime. A forum search for 'carbon felt' should give you the information you need.
Thanks all. I've had another go, this time outside in light wind, sheltering as much as possible. I managed to preheat and start the burn properly, but the flame doesn't seem as good as before. It is tinged with yellow and occasionally sputters into a bigger yellow flare. Photo below. Would this suggest the fuel is not vaporising consistently while running?
Have you removed the brass gauze roll from the lipstick tube yet? I had one where it was quite gunked up with carbon at the top end. A bit of a clean and the heat transfer/vaporising function was restored. Just a thought. If the flame is generally yellow tinged and there is a sooty residue on the pans when up to temperature, that would be an indicator of the stove running rich as the jet has enlarged. The jet is just a hole in the end of the lipstick tube, so it is a case of gently peening the tube end to reduce the hole size, which may be checked with a correct sized pricker wire, but if it aint broke, don't fix it!
Thanks for the suggestions. I tried again with a wind screen I had for a modern gas stove. It runs far better now! I also managed to start it with no flare ups this time! I'd put the difference down to the wind screen, longer priming and adding a doughnut of glass fibre cloth to the meths cup as a wick. I cut this out from a heat resistant mat I had going spare. I'm going hiking soon and am planning to take the 96 with me. Hopefully it can manage a decent fry up!
@Voxophone well done, plenty of practice indoors then out, especially in windy conditions, fill give you a feel for the priming process and give you confidence. Outdoors in gusty wind the stove can get own out, so makeshift windshielding from a rucksack may be needed. If you can sew, the period advice was to make up a fabric windshield like this: Which rolls up like this: ...to slip into a rucksack. If you can't sew, there are no shortage of modern aluminium folding options.
I rarely run a kero stove indoors if at all, start up and shutdown fumes cling to clothes enough in my garage, best used outdoors. Duane
