Weber shaft wear, what is acceptable?

Chuck Moreland · 07-20-2002, 04:06 PM

In an earlier post I described a popping noise coming from #6 through the carb. I thought it was a tight valve not closing, it was not.

While poking around I found that pressing on the throttle shaft would change/eliminate the popping noise. Hmmm. Vacuum leak around a worn shaft? Spraying a bit of starter fluid on the shaft joints suggested a potential leak but was not entirely conclusive.

The shafts have a little movement in them but I didn't think it was excessive wear.

I measured with a dial indicator. One shaft has about .008 inches movement full swing if you press firmly in both directions in a side-to-side fashion. The other shaft has about .004 inches. The measure was taken at the end of the shaft where the linkage connects.

So what is an acceptable amount of play? What are my options if these are too sloppy?

911pcars · 07-20-2002, 05:01 PM

Hi Chuck,
I had this wear on my throttle shafts as well. The limit of acceptability is how much the popping and spitting at idle disturb you. I don't think you're going to leak so much air as to upset normal part throttle and WOT A/F mixtures.

Here's an interim fix I tried that was unsucessful. There's a small piece of teflon sheet wrapped around the outer ends of the throttle shaft; I guess for friction reduction or something. This wears out and could introduce some bypass air around the shaft(s). You could try replacing them and see if it makes any difference, then start saving for the Eurometrix rebuild. This is the standard scenario for well-worn Webers.

Regards,
Sherwood Lee
http://members.rennlist.org/911pcars

Chuck Moreland · 07-20-2002, 08:12 PM

Sherwood,

What is the Eurometrix rebuild?

If I replace the teflon on the outside, what about the two spots that the shaft passes through the center throat? Do they have teflon too?

911pcars · 07-20-2002, 09:47 PM

Chuck,
Eurometrix is a company that refurbs the shaft housings. They used to be in Northern Ca but the owner, Norbert Eberhardt, passed away some years ago. The company was purchased by the current owner and moved back east somewhere. Maybe someone here has a contact number for them or has another source for this service.

"If I replace the teflon on the outside, what about the two spots that the shaft passes through the center throat? Do they have teflon too?"

The Weber exploded parts illustration shows part no. 78 (bushing) on the outer ends of each shaft; nothing for the middle portion of the housing. I don't think they're there as seals; more for a bearing surface. However, if they're gone from wear, more air will pass between the shaft and the housing.

Sherwood
http://members.rennlist.org/911pcars