Not self-imposed fun, that ‘person’ was me in response to a leaking pump. You began this thread with a reference to ‘this old topic’ (my post). Now I’m the ‘person’!!! If things break, I attempt to fix them. That particular Muka pump responded to TLC, though another example also leaked at the control valve and I haven’t yet bothered to repair it, I simply don’t use it. My conclusion, as I concluded in that ‘old topic’ is that the pump is very much the Muka’s weak spot. Too complex, too prone to leaking at the valve and a real pain to dismantle/repair/reassemble. Certainly not fun!!! John
Yes, "fun with gadgets" is one thing. The prospect of servicing that pump on a groundsheet in a flapping tent under the light of a headlamp is what makes some of us uncomfortable with the prospect of depending on that stove in real-world conditions. "Now where did that spring go?" YMMV. ....Arch
getting back to leaking mukas when i bought a cheap used muka stove it had 5 problems 1 - missing fuel pick-up tube on pump.................added pick-up from broken msr pump 2 - generator blocked with unburnt carbon at the jet end.............removed small filter at jet end of generator and cleaned 3 - fuel leak where fuel line joins the burner...............fitted new nbr o-rings, ex6.0mm cs1.9mm + ex7.0mm cs1.9mm 4 - fuel leak from pump pressure indicator................needs new nbr o-ring ex6.0 cs1.0mm? worn o-ring size in pic should be ex6.0mm not 5.0mm 5 - fuel leak from control knob..........needs 2 new nbr o-rings ex11.0mm cs1.0mm? 1 - 3 have been fixed and am just back from a trip where the muka burner worked well with a stormbreaker pump 4 - looks like just need ex6.0mm cs1.0mm o-ring 5 - once the control is removed from the pump body, the springs push the brass and rubber into the space vacated by removing the control knob....the control knob can not be pushed back in i think what needs to happen is that the 2 small brass tubes in the pump fuel line receptacles need to be either pulled out or pushed through to the cavity once they are out of the pump body the knob, with new o-rings, can be put back into the pump then, in this order, the tiny o-rings, brass tubes, springs, brass tubes, fuel lines can be packed down the fuel line receptacles
the spring retainers that probably need to be withdrawn to allow reassembly of the springs + plungers AFTER the control knob has been reinstalled
made a small hook tool from a thin stainless clip and was able to hook out the 2 brass spring retainers with the fuel tubes in the pump fully cleared, the knob o-rings can be replaced, the knob put back into the pump, and then the tiny o-rings, brass piston, spring, spring retainer + fuel lines should be able to be stacked in-order inside.....then the fuel + air pick-up tubes can be forced/glued? back in now to order another multi-kit of 1.0mm cross section nbr o-rings that contain the required 6 and 11mm size for the pressure tit and control knob still wouldn't expect to do this in the field but if they can be serviced at home once every few years for a few$ it would be great
SUCCESS.....at least for the time being after the control knob o-rings have been changed, the fuel/air mixing plunger assemblies can be loaded into the fuel + air line ports in the pump body the 3mm brass last section of the assemblies must be pushed until they hit their stops, about 14mm in if they are not pushed in enough, the springs won't pushed the end seals, 3/1/1mm nbr o-rings, enough to prevent the high pressure air and fuel from escaping or mixing incorrectly the new o-rings in the muka burner generator pivot are still holding so for now my motorcycle camping stove will be the muka burner with old black dial pump the new stormbreaker burner and pump can stay at home back-up, until the repaired burner and pump have proven themselves reliable, will be the mini, titanium burner campset, 300gm
back from weekend bike trip where the new o-ringed burner and black pump worked well as well as boiling water for coffee in record time, decided to use the little blue flame blaster to start the camp fire
back from a 2 day bike camp with the muka 1st night was disappointing as at dusk when i went to cook my pork sausages, after pumping up the muka, it didn't do its usual START with 2sec air rush followed by petrol mist instead it sort of hissed a bit then dribbled fuel...........and the pump started oozing fuel around the control knob.... so it got packed away and the little titanium gas back-up stove got to strut its stuff 2nd day got to camp early so took off the generator arm and found a clot of carbon between the gauzes at the jet end, flicked that out and also a blocked fuel-line fortunately the very long and fine jet cleaning needle in the muka maintenance kit was able to bend and poke into both ends of the fuel line, clearing the blockage put back together everything worked as normal...here simmering some water after a bug-killing boil i suspect that due to the high pressure the soto liquid fuel pump generates, if there is any blockage in the jet/generator/fuel-line, the high pressure will overwhelm the o-rings in the pump, generator banjo joint etc so it isn't necessary to change the o-rings as much as it is to ensure the fuel-line, generator tube and jet are free of any blockage unburnt carbon in the generator is not going to be blown out of the generator by finishing the burn by switching to AIR and releasing the bottle pressure through the jet the unburnt carbon particles are being stopped by the gauzes near the jet and will build up there until removed
