Optimus 930 Carburation issue

I'm having a bit of trouble getting my 930 to run correctly, i've cleaned the vapouriser/loop and can run a 4.5mm ball bearing around it so it must be clear, i've fitted a new base camp nipple but i'm getting a halo around the mantle (generic) black spots on it and then within say 10 -15 minutes the J tube starts to glow a dull red, i'm going to try another vapouriser in a bit, i've already tried a different J tube with the same result, apart from using a genuine mantle is there anything else that i'm missing?
Thanks.

 

The air gap between the nipple and the j-tube is where you need to focus your attention on.

Measure what you have now for reference and then raise it up a bit.

Mine runs well at around 12mm

 

Thanks for that, how would i raise and keep it in place if needing adjustment, a washer perhaps on the threaded part of the J tube?

 

You are absolutely right. These ones should have the factory set gap.

You might just need to shim the top up z fraction.

 

Perfect, thanks for the info, hopefully my local hardware has a few for sale!

 

They both look to be around 15mm so that'll be the issue then.

 

Is there a common fix to reduce the gap to 12mm from around 15mm and does the Petromax 3/250 250 cp China nozzle fit the Optimus 930 please?

Thanks.

 

@MG In theory, yes but I'm struggling to get a brand new unused Petromax 250 nozzle into a Petromax lantern - "adjustment" is necessary. Use a file or course grit paper to reduce the diameter of the nozzle threads a bit and make sure the threads in the brass are super clean.

 

Our friends at the base camp do advertise a nozzle for a "late" 930. Not sure what that means in practical terms.

 

They do indeed, but I'd be tempted to "adjust" a Petromax nozzle rather than remortgage the farm to pay for a genuine Optimus one.

 

I know what you mean, I put a new optimus one in a 350/350 as the old one split. Then I got a petromax lantern....

 

@Henry Plews

Thanks Henry, i hope all's well with you?

 

Apparently a generic mantle is not good for the 930's although i'm sure i've used them in the past on other 930's plus the inner cover has been slightly bent up and also the lead packing under the vapourizer could be very thin now so both could increase the gap between the mixing tube and nipple and cause the issues i have, straightening the cover and a new mantle is going to be first on the list.

 

If you have a 200cp jet that could fit the vaporizer, try it out.
Sometimes the new 250cp ones aren't exactly what they're supposed to be. Often, they're closer to 300.
I've known some that cause over-fueling and overheating on smaller lanterns and eventually the J-tube glows red hot. The whole lantern would usually get overly hot while the light remains relatively dim.

 

Thanks Myn, the original jet is a 200cp so i will try that again first, hopefully its fine as no doubt i will damage the mantle changing the jet if it isn't.

 

Optimus 930 is a 300-350 CP and should have a 300cp nozzle. The lantern is usually getting prety warm att normal running.
Try to put a colar to adjust the air gap and see if it works.
I use pretty often a combination fuel (80/20, 20% gasoline) and its working better for me ( on most lamps used for paraffin /fotogen).

 

Thanks, i'll try what has been suggested so far and see how it goes, if that doesn't work i may need to take up your suggestion.

 

Hi Mark, as has been said, the gap is factory set. Look again at the image posted by @MarkC and note how much of the vapouriser is showing where it comes through the inner hood. This may give you a clue as to whether the vapouriser needs to come up or the inner cover needs to come down.

 

Normally, a 300/350cp Petromax-styled lantern would require an air gap of 14.3mm or wider between the jet and the J-tube inlet for adequate fuel-air ratio.
If lowering it to 12mm makes it run better, that'd be new to me. Usually, the 12mm range works well for my 200cp lanterns. Nevertheless, no harm trying.
There might be more discoveries on this Optimus.

 

Thanks Henry & Myn, good points, i have another (unknown working condition) 930 that i can swap parts over from if needed, hopefully i can get both working but its the original one i want to get sorted first.

 

I have never understood why Optimus advertised the 930s as 300/350 cp lamps. The burner parts are identical in dimensions to the Optimus 200 (P). They will work with a 350cp jet, but a 250 suits them better.

 

I have a 250 jet in mine and that may be why it runs netter at 12mm.

 

My 930 also has a 250 jet and needle, it's been a while since I used it but it always performed well.