7040207. whats this valve?

[Dennis D.]

Saw this on ebay.original with the "deceleration valve", as he calls it. My L-46, 4 speed doesn't have it. Anyone?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4562963948&sspagename=ADME%3AL%3ARTQ%3AUS%3A1

[Clem Z.]

Re: 7040207. whats this valve?

on the throttle linkage side of the carb instead of a simple idle speed adjustment screw it has a idle speed adjustment with a built in dashpotto allow the throttle to close slowly so not to stall the engine.i would guess it would only be on auto trans equipted cars you can see it in the picture

[Dennis D.]

Re: 7040207. whats this valve?

auto trans would be my guess too. The 7040207 is a 4 speed carb though. Thanks

[Clem Z.]

Re: 7040207. whats this valve?

i have seen this item on truck carbs also

[Mark #28455]

Re: 7040207. whats this valve?

I also have one on my 1970 LS5 454 w/ 4speed

[Richard W.]

Re: 7040207. whats this valve?

I also have one on my 1970 LS5 4-speed w/AC.
That is a good looking carb for sale.

[Dennis D.]

Re: 7040207. whats this valve?

Are your big blocks early cars?

[Clem Z.]

Re: 7040207. whats this valve?

does your corvette have A/C? if it does that could be the connection

[Richard W.]

Re: 7040207. whats this valve?

Mine is a rather late build. June 1970.
LS5, 4-speed, AC. It has the valve.

[Dennis D.]

Re: 7040207. whats this valve?

Clem

No AC for me.( no valve either). I think that carb number would be correct for an L-46, 4 speed with air as well. Have to check your theory with L-46 cars.

[Mark #28455]

Re: 7040207. whats this valve?

March 1970 454 4 speed with A/C.

[Tony H.]

Re: 7040207. whats this valve?

Dennis,
My 1970 454 with 4-speed and NO a/c is a late July-built car and it has the same accelerator idle part.

[Joe L.]

Re: 7040207. whats this valve?

Dennis-----

The part in question is a combination idle speed screw and "idle control valve". The purpose of it is to slightly delay the return of the engine to the idle condition and it is an emissions control part. It was used on SOME Rochester Q-Jet carbs in the 70-74 period. Some Holley carbs also used a similar device, although the configuration and functional design were somewhat different.

Once-upon-a-time, I researched the part numbers of these pieces. I found the ones used for the Holley carb applications. However, I suffered a "major defeat" with the Q-Jet piece----I was never able to come up with a part number for it.

[Dennis D.]

Re: 7040207. whats this valve?

Joe

congrats and welcome back.

Would you say the piece is a california part, if found on a 70 L-46? Haven't had any responses from 70 L-46 owners. Does it fit into the carb the same way as the idle screw, or is there a different carb base for it?

[Terry M.]