Reducing those blocked gas jets

[Chris Cairns]

It seems that like our UK meths supply some of the butane gas is not as pure as it could be leading to the likelihood of a blocked jet.

I suffered several blocked jets in my Regner Lumber Jack which was partly put down to the variable quality of the Go System butane gas I was using. I was passed on a tip which originated from Tag Gorton to put some coffee filter paper behind the gas jet to trap the impurities. The problem was trying to find somewhere that stocked loose coffee filter paper, which I eventually found in a Tesco Extra branch, despite the customer services computer saying they did not sell it!

At the recent Llanfair show Doug (dougrail) suffered a partial blocked jet on his Caradoc 'Cadno' and I said I'd send him a piece of coffee filter paper. He asked if I had some illustrated instructions, so as I had a new No.5 gas jet to fit on my Edrig here are some photos of that process.



You can see the original jet was sealed in with white PTFE tape, and the replacement jet (top) has a longer threaded body.



This enlargement clearly shows the problem. The PTFE tape in the threads has been discoloured a browny tar colour by the impurities. You can also see that the jet holder has a raised rim just below the threaded portion which will influence how I fit the coffee filter paper.



This is the contaminated remains of the PTFE tape that I removed from the jet holder.

The easiest way to use the coffee filter paper is to cut a piece to the appropriate depth behind the jet, and to fold it up similar to a swiss roll, but not too thick or it could block the flow of gas. However I have found that does not always work well with these raised rims so in their case I use a rotary punch tool to punch out a suitable number of disks. In this case I used a 3.5mm punch & fitted 6 disks behind the replacement No.5 jet, and rather than use PTFE tape I sealed the jet into the holder with high temperature threadlock.



Chris Cairns

[Bill/Rubery]

Then of course you could wash out the gas tank! When I owned my crummy Merlin Monarch I had lots of blocked jets. When I washed the tank out what came out looked like the tank was made in a coal mine. I had the same things happen with a Regner 'Konrad' I used to own.....

[mikewakefielduk@btinterne]

Your post is extremely timely as my Caradoc 's burner started to spit and splutter today. Looks like I need to plan a trip to our local Tesco Extra to see if I can find some suitable coffee filters. I did try the coffee and tea supply shop in Shrewsbury but they seem to have gone eco friendly and only sell the unbleached filters now, which is fine except the filter paper is a brown colour from new.

Mike

[kandnwlr]

Then of course you could wash out the gas tank! When I owned my crummy Merlin Monarch I had lots of blocked jets. When I washed the tank out what came out looked like the tank was made in a coal mine. I had the same things happen with a Regner 'Konrad' I used to own.....

Thanks for the tip! I´ve never actually done this, although some of my first locos were bought mid-90s. **Makes mental note**

[kandnwlr]

It seems that like our UK meths supply some of the butane gas is not as pure as it could be leading to the likelihood of a blocked jet.

I suffered several blocked jets in my Regner Lumber Jack which was partly put down to the variable quality of the Go System butane gas I was using. I was passed on a tip which originated from Tag Gorton to put some coffee filter paper behind the gas jet to trap the impurities. The problem was trying to find somewhere that stocked loose coffee filter paper, which I eventually found in a Tesco Extra branch, despite the customer services computer saying they did not sell it!

At the recent Llanfair show Doug (dougrail) suffered a partial blocked jet on his Caradoc 'Cadno' and I said I'd send him a piece of coffee filter paper. He asked if I had some illustrated instructions, so as I had a new No.5 gas jet to fit on my Edrig here are some photos of that process.
You can see the original jet was sealed in with white PTFE tape, and the replacement jet (top) has a longer threaded body.

This enlargement clearly shows the problem. The PTFE tape in the threads has been discoloured a browny tar colour by the impurities. You can also see that the jet holder has a raised rim just below the threaded portion which will influence how I fit the coffee filter paper.

This is the contaminated remains of the PTFE tape that I removed from the jet holder.

The easiest way to use the coffee filter paper is to cut a piece to the appropriate depth behind the jet, and to fold it up similar to a swiss roll, but not too thick or it could block the flow of gas. However I have found that does not always work well with these raised rims so in their case I use a rotary punch tool to punch out a suitable number of disks. In this case I used a 3.5mm punch & fitted 6 disks behind the replacement No.5 jet, and rather than use PTFE tape I sealed the jet into the holder with high temperature threadlock.

Chris Cairns

Thanks, Chris. The photos are extremely revealing and I dread to think what some of my locomotives look like. Time to get back to cellar - but with rather better lighting and significantly more magnification.

[dougrail]

As I've posted elsewhere too - use good quality gas. I had been using cheap Marksman brand for a summer and it had affected my loco performance. A week or so after Llanfair I switched back to campingaz [probute] and my loco no longer suffers or splutters.