Enya 5224 'square' venturis?

Does anyone know how I might tell one venturi from another? I have two of these (different id's) intended for a 5224 .35 I bought with an r/c carburetor. I also bought a K&B NVA way-back-when. I'm intending to use the Enya for stunt.

In the event that I don't have the most restrictive insert, I'd appreciate some advice on a good-enough-to-work venturi size given the K&B NVA?

Thanks very much.

Peter Havriluk

One crude, but effective way to downsisize venturis goes like this:

Take it off the engine.

Clean it good with acetone, sandpaper or file, then acetone again.

Plug it with JB Weld or some similar epoxy.

Redrill it to the desired size, or maybe a little smaller from starters.

If you're an artist with a Dremel tool, you might try to approximate a venturi shape.

The spray bar will effecively lock your epoxy insert so there won't be much danger of having it injested.
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This is not just idle theory, I made a family of venturis for my Clown Racer this way.

On the top face of the factory square inserts in one corner there is a number, 1 2 or 3. I think 1 is the smallest.

So far as epoxy is concerned when we used G15's converted from glow to diesel for FAI T/R I have made a similar plug and drilled and tapped it to take the venturis we were using. These were in a variety of sizes changing in 0.1mm steps. The only difference with what 21835 describes is that I greased the inside of the square stack making the plug removable, held in place with a 4mm bolt or broken spraybar through the hole provided.

EDIT :- "to glow" changed to "from glow to diesel".

>On the top face of the factory square inserts in one corner
>there is a number, 1 2 or 3. I think 1 is the smallest.
>
>So far as epoxy is concerned when we used G15's converted to
>glow for FAI T/R I have made a similar plug and drilled and
>tapped it to take the venturis we were using. These were in a
>variety of sizes changing in 0.1mm steps. The only difference
>with what 21835 describes is that I greased the inside of the
>square stack making the plug removable, held in place with a
>4mm bolt or broken spraybar through the hole provided.

Ian,
I used brass tubing, swedged to fit ID if necessary. I flair the tip to fit the contour. You can make up several and interchange them. The Enys 35 will run a little better with a slightly smaller venturi opening then the #1 size.
Dennis

Hi Peter, as some said in an earlier post there is a number molded in the top of the black plastic venturi. By the way they are not square.

#1 has an I.D. of .268"

#2 has an I.D. of .280"

If you use the smaller O.S. Max spraybar/needle valve (.136 O.D.) I would stick with the #1 venturi. If you use the larger ST spraybar/needle valve (.156" O.D.) then you could get away with the larger #2 venturi but I would still use the smaller venturi if that's what you have. These old Enya's are relatively strong running engines and the the engine will still put out good HP even with the smaller venturi/larger spraybar combination.


I would not use acetone on these old black plastic venturi. I'm not sure what the material is but a quick check with acetone on an old cracked one and the solvent started to eat the plastic!

If you create a venturi with 5-minute or 10-minute epoxy, there is no need to use a release agent to assist its removal. Just heat the case near the venturi with a Bernz-O-Matic at a low heat. The epoxy softens, and easily pops out.

Roy Mathieson, perennial president of the Chicagoland Circle Cutters, has been necking down venturis for many years with telescoping sizes of brass tubing. (Being lazy, I'd prefer the softer, more malleable copper tubing.)

K&B made 2 types of needle-valve assemblies for their 35-sized engines. The earlier spray bars had a smaller diameter where they passed through the venturi. The later models were a constant diameter (bigger, through the venturi).

>Hi Peter, as some said in an earlier post there is a number
>molded in the top of the black plastic venturi. By the way
>I would not use acetone on these old black plastic venturi.
>I'm not sure what the material is but a quick check with
>acetone on an old cracked one and the solvent started to eat
>the plastic!

I wouldn't drown 'en acetone. Just a quick wipe to make sure it's fuel-free so you can get a bond.

I feel a lot more confident working with a metal venturi. But if all you've got is a plastic sewer pipe that's too big to draw, what's to lose?