Optimus fuel filter blocked?

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PT1029
Posts: 1742
Joined: 16 Apr 2012, 9:20pm

Optimus fuel filter blocked?

Post by PT1029 »

I left some unleaded petrol in my oprimus fuel bottle/pump for too long.... (I know unleaded is best not used, leave that for another thread!)
There is now some thin solid dark gunge on the bottom of the fuel bottle (I guess not a problem, it won't scrape off, so I guess it won't be going anywhere).
However, I have just tested the stove with Coleman White Gas. I checked the nozzle was clear (used the pricking needle supplied with the stove), checked/cleaned the grooves/thread on the control spindle (base of stove) and checked the pump washer. The pump feels as though it is pumping ok. But minimal pressure at the stove end (wouldn't even simmer I should think).
I guess the filter is a fine mesh, but close up it looks blocked with fine crystals of something (or is it a sintered filter?).
The instructions refer to: -
"The stove is equipped with fuel filters in the pump hose (35). These filters require no other attention than replacement as required. When replacing filter in the hose connection, the existing filter may be removed by sticking a pointed object (such as a needle) in the filter and prying it out, taking care to avoid damage to the sealing faces. Carry out leak testing as described in 4.5."
Part 35 referred to is shown below.
It does not state how to fit a new filter(!).
Last autumn when using it on gas, it quickly lost most of its pressure one evening (not overly cold ambient temperature, mid September, day time in shorts/short sleeves), I am not sure if the gas ran low (it has since run a fair time very low on gas while testing in the garden, control ste on high) or if there was/is a blockage somewhere else. In both cases the nozzles were cleared with the pricker, and the control spindle removed/checked (look a bit darkened/blacked, but no obvious detritus/soot etc).

So, questions,
1. From the photo below, is my filter blocked?
2. How do I sort it.
3. Is there another filter, the instructions above refer to "fuel filters in the pump hose"

Part 29 on the pump seems clean. I switched nozzles between the liquid and gas fuels.
Stove fuel filter close up.jpg
Stove fuel filter.jpg
Attachments
Stove pump diagram.jpg
jimlews
Posts: 1475
Joined: 11 Jun 2015, 8:36pm
Location: Not the end of the world.

Re: Optimus fuel filter blocked?

Post by jimlews »

Being a Trangia sort of chap I'm unfamiliar with Optimus.
However, you make some possibly significant observations:

The pump seems to be working... pressure at the stove end is low.

Probably stating the obvious, but I suggest that the pipe or whatever
connects the two is partially blocked.

I believe that old petrol congeals as the volatile components dissipate.
There must be some solvent product that can dissolve that residue.

Does Optimus have a help line?

Are there service agents/specialists?

Edit: You might ask at a garage what they use to clean out fuel lines/carburettors etc.

There are one or two motorcyclist types on this forum who may be able to help.

But if it were me-I'd start with the kosha Optimus fuel - keep putting that through until
you get some pressure at the stove end.
Good Luck.
rjb
Posts: 7183
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: Optimus fuel filter blocked?

Post by rjb »

The filter looks blocked. But i am not an expert. Normally you would need to blow the line back to clean it but ive no idea how you get into that tube. It must come out from the head unit some how.
good luck.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
soar
Posts: 8
Joined: 29 Oct 2019, 6:08am

Re: Optimus fuel filter blocked?

Post by soar »

Ask the members of classiccampstoves .com ,they will able to help.
PT1029
Posts: 1742
Joined: 16 Apr 2012, 9:20pm

Re: Optimus fuel filter blocked?

Post by PT1029 »

Thanks for the replies. Some progress.
I decided the filter looked blocked (rather than sintered!) and decided to prise out the filter from the end of part no 35, in the end the lumpy bit on the end of 35 came off as I did it, so filter now fully removed. While the lumpy bit was off, I put a spirally single strand of brake cable in and out and twirled it all about to try to clear any detritus - nothing obvious came out, but at least I could push the strand up to the end. The lumpy bit I put back on the end, but no filter in it.
I have had fuel emerge at the burner in small amounts. Using Coleman fuel and meths to prime, it works very briefly before fading out.
I tried using Colman gas (having changed the nozzle). I let the gas push out the liquid fuel (a notable amount came out) without lighting it, and let the liquid fuel dry off. It then worked well with the gas* Here "well" meant I could feel a notable amount of heat (breezy garden)
I then converted back to liquid fuel, but there was no improvement (brief sign of life then faded out). I wonder if the pump isn't working as well as it feels - when I release the pressure (loosening the pump in the fuel bottle), there isn't as much phfsssss as I seem to remember formerly. The pump washer is a snug fit and I have oiled the leather.
In all cases the nozzle was pricked clear, and I could see through the hole when held up to the light.
*I tried on the original noisy burner, and the replacement silent burner, on the basis that if the original burner is noisy, I can hear that it is working with gusto!
jimlews
Posts: 1475
Joined: 11 Jun 2015, 8:36pm
Location: Not the end of the world.

Re: Optimus fuel filter blocked?

Post by jimlews »

I think your next port of call has to be the pump.
Maybe some gunge or corrosion in there.
Try flushing with solvent, perhaps lighter fluid.
Proceed with caution.
If disassembly seems necessary, don't force anything.
Lay out any parts you've disassembled so you know how they reassemble.
Once again,
Good luck.
Jdsk
Posts: 24478
Joined: 5 Mar 2019, 5:42pm

Re: Optimus fuel filter blocked?

Post by Jdsk »

jimlews wrote: 25 May 2022, 9:20pmDoes Optimus have a help line?
https://www.katadyngroup.com/int/en/Ser ... 20Services

Jonathan
PT1029
Posts: 1742
Joined: 16 Apr 2012, 9:20pm

Re: Optimus fuel filter blocked?

Post by PT1029 »

Some improvement.
I removed the burner nozzle and the control rod (at the stove end). Drained off the white gas and put white spirit in the bottle, pressurised it and then let some fluid run through the pipe and out the stove/control pipe (no flame). plenty of fluid came out, all looked clean.
I also looked again at part 29 (the non return valve on the pump). The none return valve was pretty much clean, except for the metal sealing bit at the end. The O ring (blue for some reason - possible discolouring from metal corrosion?) looked ok, but the metal had some green corrosion on it. With a brass wire brush I brushed it to look clean/tarnished brass colour (no longer green), added a dab of silicon grease. I also added some silicon grease to the pump washer which I had previously oiled. It felt a good snug fit.
Flushed out the white spirit from the bottle/pipe and tried with the Coleman white gas again (NB Coleman fuel is just purchased so should be OK), priming with meths (burns clean). It was a bit sluggish to get going (it was however fairly windy), and with the OEM (noisy) burner burnt noisily for some minutes before I turned it off. I'm not convinced it was running at full wack, not as noisy as when used with petrol, and I don't think as hot (gas felt hotter yesterday). My previous experience with white gas (in an MSR stove) is it is like rocket fuel, the stove glowed red even in the middle of the day.
I'll need to try heating some water to see how quick or not it is. I'll try tomorrow, only so much you can do tinkering with flammable liquids each day!
There is hope for hot water when camping next week! Based on yesterday, probably gas.
jimlews
Posts: 1475
Joined: 11 Jun 2015, 8:36pm
Location: Not the end of the world.

Re: Optimus fuel filter blocked?

Post by jimlews »

Well done! That sounds like progress!

That green, I think, is 'Verdigris' - typical corrosion of copper.

You may have to strip and clean a couple of times before you
get the Full Monte.

You might try spraying with electrical contact cleaner which is, I think, Naphtha.
PT1029
Posts: 1742
Joined: 16 Apr 2012, 9:20pm

Re: Optimus fuel filter blocked?

Post by PT1029 »

Thanks for the advice.
The link to classic camp stoves was interesting. I didn't ask there, but it showed me there is another world out there of old classic stoves, and alerted me to the possibility of the metal pump coming loose (ie leaking) with in its plastic mount (the person knocked it out and then glued it back in).
I tried again yesterday on Coleman white gas (aka petrol), checked nozzle was clear using the pricker, ran for a few minutes before losing umph again. Checked the nozzle - clogged up (no light visible in the removed nozzle when held up to the light).
So, removed the filter housing (part 35) even though I had gouged out nearly all the fuel filter in it. Again removed nozzle/burner control rod. Swapped Coleman fuel for white spirit, pressurized the fuel bottle flushed through the pipe (plenty of liquid flow). Pressurized the fuel bottle bottle containing air only, turned on to flush out the white spirit. Checked nozzle was clear and inside surface wiped clean.
Primed with meths but didn't light the stove when the meths ran out. Checked the nozzle - still clear, but thought I'd check the priming wasn't causing an issue (unlikely, as the meths burns clean).
Primed/lit stove with the OEM (noisy burner), worked for quite some minutes (longer than before) before turning off.
Lit again, added a pot (1 1/2 mugs or so) of water which boiled in about 5 minutes. Success.
Swapped the OEM noisy burner for the quiet burner, repeated boiling water in a similarish time. Sucess
Camping next week, so hopefully it will still work!
Moral of the story, empty the fuel bottle/pump of fuel when storing, and don't leave it to "get round to it...."!
PT1029
Posts: 1742
Joined: 16 Apr 2012, 9:20pm

Re: Optimus fuel filter blocked?

Post by PT1029 »

Well, the stove got some use over the jubilee weekend (though the none cycling family members camping gaz was more convenient), and also used in a 5 day jaunt the other week.
All worked fine. Phew. Now going to the shed to empty the fuel out.

PS I have to say for what it contains, the plastic bottle the Coleman fuels come in when you buy is it very flimsy (slight increase in ambient temperature and the bottle can't stand up properly as the bottom bows out), I'd say even more flimsy than the flimsy bottles our cooking oil now comes in. Dilemma, store in flimsy bottle with original label, or in sturdy aluminium bottle but not with original label?
When camping I use aluminium fuel bottles.
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