Venturi on LA 25 spray bar hole is egg shaped

[Charles Carter]

While removing the venturi to inspect it I discovered that the needle valve spray bar was surprisingly  easy to remove.  I removed the venturi and notice the holes on the sides of the venturi were egg shaped and enlarged.  Would a delrin venturi replacement be a permanent fix?  Is there a better solution?

Charles   

[Motorman]

Unless the venturi rattles around I don't see a problem.

MM

[Dwayne]

I'd apply a little high temp silicone to make sure it's sealed good, and that should do it.

[Tim Wescott]

Is it an aluminum venturi?  Someone may have opened up the holes to make it easier to put in.  I would expect that an aluminum venturi would be less likely to have its holes spontaneously elongate than any plastic, even Delrin.  Some el-cheapo plastic venturi (I make mine from an old cutting board, but haven't challenged them with any lean runs yet) might distort from engine heat.

If you have a nice new O-ring, you need to press hard to get the spray bar hole to line up -- if you've got an old hard one, or if someone left it out entirely, then the venturi could well be loose in the hole.  I'd check the fit with a new O-ring first.  If it's a stock OS venturi then you would ordinarily use a stock, skinny, metric, o-ring -- someone may have substituted an inch O-ring and elongated the hole to match (I make my venturis to take an inch O-ring from the hardware store; if you tried it with a "correct" metric O-ring it's be loose in the hole).

[Avaiojet]

I believe you can still purchase a new one from Tower for 10 bucks.

Charles

[Brett Buck]

While removing the venturi to inspect it I discovered that the needle valve spray bar was surprisingly  easy to remove.  I removed the venturi and notice the holes on the sides of the venturi were egg shaped and enlarged.  Would a delrin venturi replacement be a permanent fix?  Is there a better solution?

Charles   

  Are you sure?  You can take a round object, drill a round hole it in, and it will be round. If you then go to chamfer the edge, you will indeed get an elliptical chamfer, but unless you to all the way through, the hole is still round. Are you certain you are looking at the actual through hole and not getting fooled by the shape of the chamfer?

   Brett

[Charles Carter]

Hi Brett,
I double checked and the holes for the spray bar entry and exit on the sides of the venturi appear egg shape or elongated slightly (vertically).  Thanks to everybody who has commented.   

Charles

[Bill Johnson]

I noted that the OS OEM venturi I bought for a 25FP would not seat so the NVA would fit if I used the o-ring that came with it! I ended up installing it without the o-ring and sealing it with red RTV but I can see how someone might, to get the NVA installed, think it best to just drill through the venturi, elongating the hole.

[REX1945]

.......If you have a nice new O-ring, you need to press hard to get the spray bar hole to line up -- if you've got an old hard one, or if someone left it out entirely, then the venturi could well be loose in the hole.

   I usually replaced the OS spray bay/NV wit a Super Tigre one. Being larger in diameter required the holes to be
enlarged. Still there's a real problem compressing the stock "O" ring enough to get the spray bar to pass thru.

    The larger dia spray bar reduced the air flow sufficiently to keep the engine from "running away" when hot.

Rex