Guys,

I noticed at the strip last night that my car was idling very bad and my times were off. I turned up the idle screw to get through the night then drove it home. This morning I started looking for vacuum leaks and found that I could move the primary throttle shaft up and down about 1/16".

This is the second brand new Holley O-3310 (750cfm vac secondary) that I've had this problem with in the last three months. I thought the last one was a fluke, it leaked on the secondary side.

I'm a long time Holley fan - used them since I was old enough to drive and generally swear by the brand, but am starting to wonder. You guys think I just have bad luck? Could I have some obscure problem with my linkage setup or has there been recent quality problems at Holley?

Thanks for the input.

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68 Camaro, 383 small block with TH350 trans. 12.4's and never trailered.

I have found over the years that if you have a fairly stiff return spring, it should be mounted in-line with the throttle linkage or it will eventually kill the throttle bushings. I know most people mount them on the opposite side of the throttle pivot point but after fighting the same problem on 2 different holleys over the years, this seemed to help a lot. I do all my carbs this way now and have never had a problem since.

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova

Travis has it right. You can't have the spring working against the linkage. On a Holley you can change the bushings easily on a Qjet it is a real pain.

Are you sure it's that loose?
A loose shaft would only affect idle quality and idle speed.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350 Can-Am Vintage Racer

[This message has been edited by davidpozzi (edited 08-05-2001).]

Yes, it's that loose. With the engine idling I can change the engine RPM by 200 or 300 RPM by just moving the shaft up and down (of course being careful to keep the throttle blades fully against the idle screw). The engine acted pretty lean when I was staging and it would pop once or twice right when I opened her up, my 60' times were up to 1.85 from 1.74. Trap speeds were OK though - still around 108 mph.

I actually have a fairly light return spring (just a heavy foot), but the spring is pulling the same direction as the throttle cable and is attached to the throttle cable bracket. I'll have to change that when I replace the carb.

How do you change the bushings Oger? Maybe one just popped loose or split or something. I've rebuilt a few Holleys, but never messed with the bushings.

As it turns out, the receipt for my carb is about the only receipt I do not have. Looks like I'll either need to fix the one I have or talk to the wife reeeeaaal nice hoping she'll "give me permission" to buy a new one. LOL.

[This message has been edited by Eric68 (edited 08-05-2001).]

[This message has been edited by Eric68 (edited 08-05-2001).]

Update . . .

The movement in mine seemed excessive even when compared to other Holleys. I looked at a friends 650 DP and a new Avenger and both moved less than mine.

So I took the carb apart and pulled the throttle shaft out. There was some scoring around the shaft but the surface of the hole in the baseplate looked OK. So I put it all back together and called Holley.

I talked to a guy named Chris. It took him a while for him to convince me that the throttle shaft could move that much normally. He says that it has to leak some or when the engine gets warm the metal would expand and the shaft could seize. He wanted me to put the carb back on with a new gasket and check for leaks again.

Replaced the gasket, fired it up it's running like there never was a problem. I suppose it could have been a bad gasket (I can't see anything wrong with the old one though) or maybe twisting the throttle shaft in and out of the base plate knurled the hole in the base plate and tightened up the fit a bit. The shaft doesn't seem to move as much up and down as it did before - weird, but its fixed.

Thanks for the help.

BTW - Holley says that there are only bushings in the secondary side, no bushings in the primary side. Hmmm.

Correct - no bushings in the primary shaft holes; professional rebuilders can drill them out and install/ream bushings for a good fit. Rig up the return spring from the top of the throttle lever (where the linkage connects) FORWARD so the shaft isn't under constant rearward pressure.

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JohnZ
'69 Z28 Fathom Green