Help with my new optimus 8r and the pump.

i just got myself an old Optimus 8r in really mint condition for the bargain price of $15 CAD!!! im so happy. i placed a wanted ad on kijiji.ca and got a reply within days.

it also came with a pump, but i just want to clarify how the pump fits. does it just go over the cap i have on the stove as a press fit? if so i think the little o ring inside the pump is perished and needs replacing as it wont fit over. or do i need a different tank cap? i cant find any images of the pump i have, only images of the angled pump.


also, the stove hasnt been used for 15 to 20 years, so i tried lighting it but had no joy. does anyone have a link to the manual for this stove so i strip it down and give all the jets etc a clean.
or give me a quick guide of what to do to give it a general service.
thanks
Scott

 

in fact, i just found a video on youtube [media=youtube]9A0Yu24z4fc[/media] and it seems to show i need a different cap for the tank to use the pump.

does anyone know a good place to get one of the caps, is http://www.packstoves.com/ the only option?

alos, how much should the valve turn? mine only seems to have about 3/4 of a turn.

also, is there any way to tell the age of the stove?
thanks

 

The first thing to check is the seal on the filler cap. If it is hard it may not be making a good seal. I've used washers obtained from the local ace hardware to replace one on a svea 123r a while back. You should look for nitrile rubber. does the valve seem to be working? When turn it all the way to the clean position do you see a needle poking out of the jet? Does it retract when you turn it away from the clean position? What was the exact lighting procedure that failed? You might check with A&H enterprises on that cap to go with your pump.

If it's not the rubber seal on the cap that is causing the problem it may be that the wick has failed. There is a detailed instruction under the fettling section.

This EXCELLENT INTERNAL LINK is pretty much exactly what you need...

The CAP AT A&H

 

hi,
i took it apart as per that guide. well, didnt seperate the burner from the tank. ill do that if it still doesnt work. the needle is working fine. so ill try it again, and then maybe the seal needs replacing.

thanks for the info so far.

 

The mini pump is an auxiliary only to be used in very cold conditions when the stove won't self pressurize. Years ago I bought one to use with my Svea 123 in the Sigg Tourust Cooker. Never really needed it, but it is handy to get the stove to squirt out a little fuel for preheating.

Do not pump more than three strokes or you are very likely to get an overpressure situation which is doubleplus ungood.

Gerry

 

Yeah try the simple stuff first... Also about that video... that guy pumped that stove up way more than he needed to. If you do get the right cap i think the general consensus is about 3-4 pumps max. The thing is... the stove was designed to self pressurize anyway. And it will self pressurize regardless... so if that guy were to actually cook on that stove after pumping it that many times (ex... run it long enough to warm it up) he would be in danger of blowing the safety valve. I just got a plastic eye dropper from walgreens. ($2) A couple of little squirts of coleman fuel or denatured alcohol in the priming pan is all you need. Wait till the priming flame is just about out then open the valve.

 

ok, i dont think i will rush to buy a new cap. as hopefully i will get it going without the pump. i knew it was only really for use as a back up in cold weather.

however.....i just tried it again, and it started to pressurise and feed fuel into the burner after priming it with an eye dropper and lighting it, but then fuel started leaking from the the fuel cap and i had to blow it out.

so i checked the seal again and sure enough when i tried to prise it out it snapped into lots of tiny brittle pieces. so i need a new seal, but then i think it would be good to go. everthing else seems ok, and the fuel seems to be coming into the jet OK, so i guess the wick is fine.

the only other bit of concern is the fuel cap seems to have a little rattle inside it, and if i blow on it i think air leaks outwards. is this normal?

ive given it a good clean up, and it looks great now. nice polished brass tank.

does anyone know of any Canadian sources for the rubber o rings? what size is it? is it something i can find for another item but happens to fit?

 

Hi, you will need to replace the rubber botton inside the relief valve. a few of the people feel it is unsafe to do so.

So do it at your own risk.

As for me, I replaced any hardened rubber on my fuel caps, and the fuel caps serve me well, and I do not wear any brass ornaments on my face so far (as in the aftermath of an explosion, he he). Just do not alter the little spring inside the relief valve.

You can check out the plumbing section and get packet of assorted O rings. Outside Diameter is 3/4 inch, and they work pretty good on my numerous fuel caps.

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The picture is small, but if one puts a coil of fiberglass rope (wood burning stove door seal) in the priming cup, one can enhance the priming action for positive start. I put another one between the fuel tank and the heat shield, in order to heat up the tank quickly. I use about 1/2 squirt of dropper full for warming the tank.

Oh, by the way, your 8r is much desired over plain cased ones, for it has the decal and embossment. Earlier ones have chromed tanks.

 

are you saying because i can blow air through the tank lid i need to do this?

if so, how do i open the lid safety valve? and what do i replace it with?

ill try and get some o rings tomorrow then.

thanks for the info.

 

in fact, ignore that, i have tried again and if i seal it more tightly with my lips i dont think any air is going through the valve in either direction no matter how hard i blow.

so it must have just been the rubber o ring that was leaking. hopefully i can find a replacement at the hardware store.


out of interest, if the embossed model is more desirable, what age is it? i think its pre 1970 isnt it as it has the slot on the fuel cap, not the hex bolt type. and from the old manuals on this site it is more like the 1960's one than the 1979 one as it has the red plastic handle.

 

For the age of a stove, I do not think I can shed any light. I am certain some one else could supply with a better answer.

I have one with chrome tank, and I think it is late 50's. And it has red handle key just as yours. I think Optimus used whatever was on hand, until the stock ran out, and then progressively simplified the design, in order to cut the cost.

 

ok, thanks. im guessing its sometime in the 1960's.. but why is the embossed one more desirable?
ill take some more pics once ive got it going well and cleaned up a bit more.

just got to have a good look through my shed for a suitable rubber washer, or take a trip to the hardware store.

i see a lot of people are using that fibreglass stove door sealer rope to pack into the spirit cup for easier priming. how exactly do you pack it in and make it stay in place?

this pic shows what i mean best (just the spirit cup bit, not the bit under the tank)

 

I make mine 1-1/2 go round they about 3/8 thick just put a some wire on the beging end tie to post then wrap tie the other to post push down make somewhat flat dont take much wick

 

I think older one is desirable, based on the principle that pertains to wine and friends--except women, as some old guys seem to believe.

But the real reason is that it has the nice figure that is pleasing to eyes. Optimus went into trouble stamping that logo, and I would like to recognize their effort in an appreciative manner.

I think you've got a whale of a deal on that compact package.

 

yes i quite agree, it looks very nice with the embossed logo. i wonder if there is an archive showing the years when they did that. i have seen a much older one without the logo, and newer ones. and it seems in 1965 the handle changed to a larger plastic one, and then later again changed to the metal tool type key.

so i think that it is most likely pre 1965, do you agree? if so it makes my Trangia 27 seem young, despite the fact i have owned that Trangia since i was 5 (so 21 years!) it cost me ?50 (well cost my mum) British pounds when i started cub scouts back in the UK. and i have used it every year since, and it came over to Canada with me when i moved here last year. she still laughs that she told me it was a waste of money and i would never use it. but now she agrees it was a good investment...

ive got someone picking me up a rubber o ring as we speak in town, so ill hopefully have it fired up before the day is out. but the brass tank is now nice and shiney, and apart from one small area in the corner on the inside where the paint is a little chipped it looks more like 4 months old, rather than 40 years!

 

Since I have no expertise, I will keep silent on guessing the age of your stove. I do not think any one can tell the age of 8R for sure. The precursor to 8R is 8, and it came in a more squared edge box. The spindle was a lot thinner than it is on 8R. You may be able to find some sample pix somewhere on this site.

Do share with us what the stove looks like, after you got it going. I am pretty sure there will be many who would appreciate it.

 

well i got it going! i had to take apart the safety valve as it was leaking. i replaced the little bit of rubber as it was solid and all distorted.


it burns like a jet, really strong blue flame and roar! the burner gets red hot..

ill get some pics of it going soon.

 

well done , sit back with a cuppa tea and consider it a job well done ,how about a photo of it running?

 

yes i will get some pics tomorrow. i think i might still buy a new tank lid for it as when i had to take the one way valve apart it did a little damage to the finish of it. and i had to cut up an old screwdriver to fit the special screw head! plus the tiny piece of rubber i had to cut out of a bigger o ring, but seems to do the job nicely..

just out of interest, how hot does the tank normally get? i found when using mine with a frying pan more heat was put into the tank as the flame was bent closer to the tank. and it was hot enough you couldnt touch it for more than a few seconds.

 

I would say that degree of heat in the tank is okay. That is how hot my 8R gets, after a prolonged use. It gets there quicker, if I heat the tank separately. The same hotness is detected on the fuel tank of Svea 123(R). The tank should be hot, in order to produce the internal pressure to push out the fuel vapor.

You will know when it is overpressurized, when you open the fuel cap immediately after you shut down the cap: it pops rather loudly, spewing warm fuel.

You will notice the flame die down, conversely, when you expose 8R's fuel tank to cold wind in winter. That is when the mini or midi pump comes in handy.