Carb help please !!!1

[cliff]

To all the carb experts out there, here is the problem.
I noticed that all the main venturis in my Dellorto 36 mm carbs were spinning and not fixed. I check and there are no main venturi attachment screws. I checked in the tech book and the dealer and this is true. Only the auxillary venturis have securing screws. I also noticed that one venturi had dropped down and has probably bored its way down. The carbs run fine and have not had any problems. Apparently the venturis are just supposed to sit snug in the bore....is this true. If so can some high temp silicone sealant be used to fix the venturis so that they don't spin. All replies are greatly appreciated.

Thanks

[Conrad W Peden]

Have you considered that maybe the body of the carb is the problem and not the venturi?

I had 36's on my Beetle and with the lack of room in the engine area hit the carb on the side of the engine area when I broke the tranny mount, guess I should have put the strap on sooner.

It cracked the body of the carb where the aircleaner screws went in. I could tune out the problem the crack caused but the crack was still there.

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CWP/VIR
72 914 L20E in rusto.
73 914 L20E 2.0L in resto.
http://members.rennlist.com/a914lover

[sammyg2]

I know some about webers, but not much about Delortto's.
Mu suggestion would be to use locktite red instead of silicon rtv.

[Jake Raby]

The secondary Venturi must fit snug, to help resist fuel seepage.

the venturis on the other hand need to fit a little loose. i have had to remove them with punchs and hammers before, a bad and scary experience.

I love DELLS. the type 4 engine is optimized with dells, more so than Webers, also the Dells flow about 40 CFM per carb more than a Webers of the same arrangement..

NEVER EVER GET SILICONE OF ANY TYPE AROUND ATOMIZED FUEL MIXTURES!!! the result is a slimy glue that will ruin almost anything in the engine...

[cliff]

Well is silicone is bad, how about JB weld or loctite. Would that stand up to an atomzied fuel mixture. Is this a possible way to fix the problem. I just don't understand why those venturis are moving around in there.

[scriabin]

Hey Cliff,

I've been running Dell 40's for a few years with venturis ranging 34, 36, and 38, and though I have not experienced the problem you describe I wanted to ask how you first assessed the fact that the venturies were 'spinning'--(meaning, during a rebuild while the carb was still apart? or after installed and running? And yes, they are merely a snug fit, with the chokes secured on top as you mentioned). Also, is there any lateral play of the venturis in the bore? And is the issue common to all four venturies?
Fortunately I've always encountered only the expected resistance of a snug fit when removing venturis, but have never considered the idea of attempting to spin one--subsequent to installation.
If you're still concerned, and have, or can get hold of, the tools to precisely measure the carb inner bore dimension where the venturis rest, and the venturi outer dimension also, I would suggest doing so.
Otherwise, just check to confirm that the secondary chokes are properly seated with the dimple aligned to accurately receive the point of the set screw before resorting to the dubious option of putting any sticky foreign substance down the bore. Best wishes.

--John

[cliff]

That is a good idea John. I will probably check the auxillaries first. I noticed the spinning when the car was running by accident. One of the chambers would not tune at all, lo and behold, the venturi was spinning and also had some vertical play. Coincidentally, all the venturis are spinning, one is worse than all the rest. It has actually bored into the chamber a little and hence the vertical play. On this one, good securing with the auxillaries may not be enough...any suggestions.
Thanks
Cliff