Tuesday 10 November 2015

Quick Word About.......Fire Safety: Carburettor Fuel Inlets

I’m resurrecting something that has been raised on the CCC (Citroen Car Club) forum, as any safety tip is worth repeating.

For those that don’t know, there is a possibility that the brass fuel inlet fitting can work lose from the carburettor body.

Loose Inlet Pipe (Photo: Colin Smith)
If this happens while you’re driving, your pump will spray fuel over the engine as you splutter to a halt. If you’re lucky, you push the pipe back on and off you go. If you're unlucky, you get a fire....... 






Photos: Gerry Freed
The solution is to replace the brass push-fitting with something that’s going to stay in place and hold the hose tight. With that in mind, Richo - a much respected contributor to the ‘Aussiefrogs’ forum down in Oz - made threaded and barbed fittings and sold a few batches of kits on a non profit making basis. The kits consist of a fitting machined by Richo, a cutting tap of the correct size and pair of hose clips. The fitting has a threaded end to go in the carb body and a barbed end that the fuel pipe fits to. Richo also sold just the fitting if you were so inclined.


Richo's Fittimg
The fitting can be used on a Weber or Solex carbs.
Richo's Fitting - Fitted......
Reports from grateful customers in Oz prove they are a hit. Here is some fitting advice by Richo, lifted from Aussiefrogs:

"The kit fits either the Weber as fitted to the later 21 and 23 engines as well as the Solex fitted to the D Specials. If your D was built from 1966 to 1974 then this kit fits.

I recommend removing the carburettor top and then tapping the thread required, BUT others will simply slap some grease on the tap then gently and carefully, making certain the tap is square to the hole, turn the threading tap a couple of turns, remove the tap, clean off the swarf, put some fresh grease on, thread some more until the job is done. At the very least, remove the filter nut at the top left side of the unit and block the access. You can also gain access to clean out swarf.


A small amount of thread tape, probably one wrapped turn will be sufficient. Next, thread the new fitting into place, with your 11mm or 7/16" wrench. I prefer to also use the hose clamp supplied in the kit on the new fitting, even though the barbs will hold the plot, no worries."



The last few kits that Richo made (in 2013?) found their way to New Zealand and the safe hands of Roger Simpson. Kiwi’s have been slow to take advantage of these and Roger is happy to see them go to good homes in the UK. Following the trail from Aussiefrogs I was able to contact Roger who happily sent me a couple here in the UK. Roger now about 6  fittings left. No Taps. Price for the fitting for NZ customers are NZ$15 (about £7) including postage. Contact Roger direct via the ‘contact’ form on his website and he’ll give you a price for the UK: 




This will not include a tap to cut a thread, so you will need to purchase your own. The outer diameter of the brass push-fitting you are replacing (and so also the hole it leaves in the carburettor body) is about 8.15mm. To cut a thread, you need a tap slightly larger, which is why these fittings have an M9 threaded end. You will therefore need to buy a M9 x 1.00mm bottoming tap. Or contact me and you can borrow mine.


Colin Smith here in the UK picked up on the same idea. Colin used a 1/8” BSPT brass tail fitting readily bought in the UK, for example from Tom Parker Ltd for the princely sum of £2.04.

<<EDITED JUNE 2019: just guesswork, but I now believe it’s a 1/8" x 5/16" fitting that Colin used. 1/8" refers to the imperial thread size of the threaded end. If you buy an imperial fitting, you will need to buy an imperial tap of course. A 1/8" threaded end has a diameter of  about 9.7mm so before you tap for 1/8", you may need to drill out the hole in the carburettor to about 8.7mm or 8.8mm - otherwise your tap may be too tight for the hole.


BSPT also means that the fitting has a slight taper on the threaded end, this would mean that it got tighter as you screwed it in. there is a risk of it then cracking and splitting the carburettor body if you are too forceful.  This could lead to a fuel leak - the very thing you are trying to avoid.....So, instead, try to find a 'BSPP' variant as the threaded part will have parallel sides - just like a bolt.


5/16" refers to the internal diameter of the rubber hose you will push on to the fitting. 5/16" is about 8mm so the size of the DS fuel pipe you would use with the original non-barbed end piece.>> 


So anyway, you can buy off-the-shelf fittings that will do this job. I think Richo’s fittings are a little less-obtrusive than the off-the-shelf ones but there’s not much in it and at the end of the day, either version is better than an engine fire.


EDIT: fast forward to my post dated 30 June 2018 HERE and you can see how I got on fitting my 'Richo' fitting to my Weber carb.


If you don’t fancy your ability to do this without messing your carb up (or causing a fire!), Colin first tried a less elegant but equally effective solution using a tie rod of copper wire held on with jubilee clip. 

You can find Colin’s write up and fitting advice for both methods on his blog:


I hope this provides some food for thought. If you want one of Richo's fittings, contact Roger in NZ while he still has a few left

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