After reading some good recent posts about tuning carbs and setting timing, I thought I'd give it a shot, so I bought a vacuum gauge today. Wasn't easy to find either - I think I got the only one in the city.

Anyway, when I took it out of the package, I noticed that the needle was not on zero. You can see it in the photo.

The second photo (I'll post in a minute) shows the back of the instruction sheet, and it says that you can remove the lens, then remove and reposition the needle.

Has anyone ever had to do this? Did I just get a gauge that's been knocked around on the shelf over the years?

Also, the instruction sheet calls it a "bourbon" tube vacuum gauge, but I looked it up and I think it is supposed to be "bourdon".

Pic 2

Simply remove the cover and reset the needle. Thats why there is a screw head in the center of the needle.
Very common--especially with gauges that read both positive and negative pressure

I went ahead and reset it to zero - it doesn't have a screw though, it's just pressed on. The instruction sheet says pull it off with needle nose pliers.

Hope it works OK - seems to be pretty cheap quality.

Only cost 20 bucks.