fuel tubing size

Surfer_kris wrote:.........The best is too use an even smaller line for the clunk, but then one has to make ones own clunk too (quite easy though on a lathe).

For a quick and dirty clunk (for those of us without a lathe), use a piece of brass tubing and slip 1 or 2 wheel collars over it. Let the tubing extend beyond the collar(s) so that it can suck up all remaining fuel from the corners.

Great idea Andrew!
Thanks

steve thornton wrote:I've been trying to break in my Big Mig 061 and found that the small tubing won't fit my fuel filter, tank, or go onto the needle of the engine very well. It seems that the larger size comes off too easy.  I need to buy some new tubing and don't know what to get that will fit all the fittings.  How do you set up your fuel system on your test stands?
Steve

I've posted this idea a few times.. but I think it could really be of help here. Try using a larger size silicone line.. and "twist it" into a short (1/4"L.) piece of alloy tubing that's slightly smaller than the line's outside diameter. This will compress the line where it needs to fit tightly.



I used a med. size line on the spray-bar nipple of this Cox back-plate. You can see the difference in size on the left vs. the right; where I used small size line to seal the needle-shaft against air-leaks. However; a larger size line may be too stiff for a small tank's clunk to flex enough to function properly though.. This mod was done to lessen the resistance for fuel to flow in a suction-only set-up.. having an oversize air-intake.

Thanks Roddie,
I have to wonder how you guys come up with such innovative ideas!

Steve, I've been using some blue silicon line I get at the LHS for years, and have never had any 1/2A equipment that it wouldn't fit. I use it on all Coxes, Norvels, MP Jets, feeding from bladder systems, etc. So far I haven't needed any tricks or improvisations to get a good fit. It might be Sullivan, but when I get in the shop this afternoon I'll measure it and call the HS and see what brand it is.
Rusty

The 2x4 silicon ones work well and are very easy to find as well.
Here is a link to Radical RC for instance; Fuel Line

Easy to make.. Use a larger line to lessen resistance to flow on a suction-feed/hard-tank. These two examples are with silicone line who's diameter is reduced by at least 30% when twisted into a sleeve/collar. The sleeves are made from common K & S alloy tubing. I used sizes 7/32" and 1/4" cut to a length of about 1/4" for the sizes of line that I had on hand.

In this cluster, there's common sm. size (1/2A) line on top with larger diameter lines below.. which are shown "left" with out and "right" with a sleeve.



A tight fitting line is less likely to fall off.. or leak air. Pairing this set-up with a tank having larger fittings should provide for a much less restricted fuel flow. It might help improve a suction-feed on an engine with a large diameter venturi.