Recently I found a battered but spirited 111B owned by a Scout Master near me that was within my budget constraints, with a picture of it running. It still had the old fuel in it from when the guy had gotten it. It turns out he got it fired up with an external meths prime because the valve didn't want to pass fuel and it wasn't exactly running correctly. As soon as the cleaning needle came up into the jet it would pop and shut down. It followed me home anyway. Not much to look at.... The pump cup looked oiled and in good shape and fill cap seal seems to be pliable, the tank appeared to be holding pressure. When I opened the valve at home I got a dribble of fuel so I pre-heated it and got it to start and run, trying to run some fuel through it. It still popped and shut off when the valve was turned to clean. It runs and kind of tries to roar but it doesn't really seem to have it's heart in it. I believe it's bleeding pressure through the NRV, I caught the pump rod backing out slightly, not very fast but enough. I have an NRV tool and new pip and a cap seal inbound.
@Oldhenry1 given that it is a 111B you should also consider if the pip in the safety valve built into the filler cap along with the filler cap seal have hardened with age. regards John
Does anyone make a wrench to fit that 5 sided safety valve in the cap or do I have to make something that probably won't fit very well? I will say that orifice in the cap isn't plugged full of crud and I can see the spring inside clearly, a positive sign. I ordered an NRV wrench and some gaskets and pips from the UK but after I placed the order and paid for it I got a note asking for additional funding for tariff fees. They weren't going to deliver until April anyway so I cancelled the order and now I'm back to square one on tools and parts. If anyone knows of a good source for an NRV wrench and seals in the US, I'm all ears.
I just ordered a multi sided SRV tool from Korea, arrives today or tomorrow. A search on the bay would bring one up. I’ll post a link in a bit. Duane Pardon Our Interruption...
Be aware that the pentagonal caps are often glued/loctite-ed in place and you may need to give it a waft of heat to break the bond. Occasionally you'll still damage a cap but its a risk to be taken. It may also be the case that the burner is slightly clogged if its been run on regular gasoline, if thats the case it will need heated/quenched, but cross that bridge if/when you come to it, see if the seals sort the issue first. Be mindful in operation that these don't have a valve to lock the pump out in use, so if you see the pump rod moving or spot any white gas appearing out the end, shut it off immediately! I've used mine for years, its a great stove, just don't walk away and leave this one unattended like you may do with a Kero. Otherwise a straightforward fettle, good luck. Alec.
All of the B’s that I have or had, needed the pip replaced and a sure sign is the pump shaft rising. Unfortunately too is the pump with a leather cup is about the hardest to get back into the pump tube, even with the help of a dental pick or the like. Duane
I've only worked on a few 111's but another thing to keep in mind is that some have the old style optimus one piece molded pips in the NRV. In that case you'll need the little brass pip holder cup. Last I looked, Fettlebox had these available. Ray
Nice find. Just to reiterate @Majicwrench: Yes, that is normal. The cleaning needle will block the jet, there is nothing unusual about what you are witnessing. Just don't turn the control that far unless you need to clear a blocked jet (seldom necessary in my experience). The pump rod may back out less than an inch or so and then stop, that's usually ok, but if it continues beyond that, check to make sure no fuel is getting into the pump tube (worth keeping an eye on even if you have worked on the check valve).
I've had 8R style stoves slow down turning to clean but not shut off like that, I guess it surprised me a little. I may have turned it to clean a little too quickly. I'm glad to hear that it's normal. It seems to run a bit better the more I run it, once the tank gets warmed up. The pump rod will back out about a 1/4"-3/8" during a session, it's enough to concern me. This one went back in the tube without much drama. I cycled the pip in the cap a few times just because I could. It needs new seals for me to trust it much further.
@Oldhenry1 Glad to hear it is running better -- it looks good. If there is no fuel in the tube, I'd not worry much about the small amount the pump rod backs out. That often happens, and seems to be stove-dependent (in my case). It is most likely not due to leakage of fuel but, instead, the expected result of a residual small amount of trapped compressed air that was not expelled from under the pump cup into the tank. And, that air warms and expands. Some users here recommend giving the pump knob a few spins while holding it down -- I guess that may help vent air remaining under the pump cup, I've tried it with mixed results.
Thanks @itchy It's got fuel in the bottom of the pump tube so I didn't dodge that bullet, at least the cup is nice and pliable and reinserts into the tube relatively easily. I tried re-seating the pump rod during operation but it still creeps out after doing so. Does anyone know of a quality NRV tool available in the US? I'm not really keen on waiting for over a month for one to arrive from overseas.
Many here have Cobbled one up from different tools or hardware. Maybe someone can post some links. Duane
I do have the seal kit coming from Fettlebox... I'm sure I could probably make something that might work if I had the dimensions of the NRV, it's kind of hard to measure accurately at the bottom of the pump tube like it is
A slot 5mm wide by 5mm deep usually works . I find old 1/2" oor 9/16" bolts work well. And wrap some tape near the end to keep the tool centered and protect the pump tube.
