The Stovebolt Site Forums The Shop Area General Truck Talk Newbie Vacuum Gauge Question

I’ve been having a difficult time getting my carburetor’s air/fuel mixture just right. I tend to set it too rich.

I would like to use a vacuum gauge but I’m not sure how to hook it up once I buy one.

There is an intake port just below the carburetor on my 235. (see the first link below, lower left after the PCV). Should I use this port?

http://i4.tinypic.com/10furl5.jpg

http://i4.tinypic.com/10fuxz5.jpg


What is an optimum reading on a vacuum gauge for the carb mixture?

Thanks for your help.

Mark

I have a vacuum gauge installed on the dash of my '59. I used the same port on the intake manifold where the vacuum windshield wipers got their vacuum.

http://www.flickr.com/photos/11159813@N00/151949993/

When using a vacuum gauge you want a reading from a place in the intake manifold where you will get a good average reading from all of the cylinders. You could easily hook up a temporary gauge in this location.

On a stock engine you should have a constant reading somewhere between 18-21 in. Hg. at idle. If the carb. is adjusted properly the needle will not move at all. If the mixture is rich or lean there will be an irregular drop in the reading. A vacuum gauge can help solve other problems as well.

Here is a web site that might help you out also.

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

Good Luck

I picked up a gauge on the way home. I don't have the vacuum windshield wipers like your truck but I see the correct port.

Thanks again for the info. and link.

Mark