Holley Throttle Shaft

[Sheldon S.]

My car is a 65 coupe with the 327/350Hp engine. Its has the 2818 Holley carb on it. I bought the carb as restored rebuilt when I did a full resto on the car. Ever since it has had a small puddle of gas on the manifold just under where the throttle shaft is. The car and engine only have about 1500 miles on since rebuild. Last week I had the car out and drove it everyday for a week and now the leaks have gotten worse. The throttle shaft have a little movement where they go through the throttle shaft plate. I am assuming that this is where some of the gas is leaking from, there are some gaskets leaking now also. Will gas leak through a sloppy throttle shaft?? Does anyone know how much movement is there supposed to be? And can someone recomend where to get the throttle plate rebushed?? Thanks in advance

Sheldon

[Timothy B.]

Re: Holley Throttle Shaft

Sheldon,

IMO, the problem is a gasket sealing problem and it can be caused because the surfaces are not flat between the different sections of the carburetor. The gaskets can dry out if the carburetor sits for a long time and cause this. Look in archives as you can repair this at home if your handy with Holley.

Another problem causing internal leakage after shut down and fuel on the throttle blades is a float level too high. If you have gaskets leaking, try the above first then set float level to bottom of weap hole and I bet your problem will go away.

Also, check the heat riser for operation but don't block it open, because the engine needs this heat for proper fuel vaporization.

[Gerard F.]

Re: Holley Throttle Shaft

Sheldon,

A sloppy primary throttle shaft would more than likely cause a vacuum leak, and maybe not a gas leak.

As Tim says, the problem may be a gasket problem. I would think the gasket between the main body and the throttle plate above the shaft or some warping of the main body or throttle plate.

Both the looseness of the shaft, and planing of the surfaces should have been addressed when the carb was restored. So you might want to ask the restorer what he did.

Take a look at the article in the Spring 2011 Restorer. The throttle shafts can be rebushed but it is a job where you have to take the throttle plate down to individual parts, and then have bushing reamer kit. For one carb, it would probably be cheaper to buy a new throttle body complete ($150-$200).

If you do get a new throttle body, you can then address the throttle plate gasket, as well as the planeness of the main body. If there are only six throttle plate screws, it is recommended that you tap the extra two holes and install two extra screws between the throttle plate main body to prevent future warping.

The other option is to just try to tighten everything, check the other areas as Tim suggests, and maybe live with it, it's a Holley.

[Clem Z.]

Re: Holley Throttle Shaft

check for fuel dripping out of the booster nozzles and falling on the pri butterflies and running out the shaft. the clearance on a new carb for the shaft is .008 and the shaft is not designed to prevent fuel leaks in other parts of the carb.