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In working on my tune-up and fine tuning my 1929, a fellow Chevrolet guy recommend I set the idle via a vacuum gauge. Adjusting Idle Adjustment Screw & Throttle Lever Adjusting Screw.
I was planning on hooking the vacuum gauge to the connection where the wiper motor connects hoping to get a good strong (ACCURATE) Reading. in doing this WHAT is a good reading to look for on the gauge ?? Figure running at idle approx. 300 RPM ?? Considering the gauge reads vacuum in Inches of Mercury (Hg)
Also if there is NOTHING connected to the other end of the vacuum connection, where the Wiper Motor should be would this affect the running of the engine ?? seems it would result in a vacuum leak = sucking in air !!
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you know I just found a post from 2009 here: Mixture and idle speedThe vacuum on the manifold is measured in inches of mercury, and the vacuum reading should be around 17 to 20 inches of mercury at idle. Coming from the JY Dog I take these are good numbers...
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If I am understanding you correctly an open wiper feed hose would be a big vacuum leak.
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Yes that was Question 2...
...which I believe would add to rough idle and such
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Yes and more. Try plugging it up and see how it runs.
Dave
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well since the wiper valve is closed, there is no leak, I get about 15 Hg at the manifold and with the valve open I get about 15 Hg at the wiper connection. so as long as the valve is closed then NO Vacuum leak here. 15 Hg on GaugeStill got the leak around the Carburetor/ manifold but others issues first...
Last edited by BearsFan315; 08/07/14 08:22 PM.
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Ok, today after cleaning the carb, I put it back together and hooked the Vacuum Gauge to the Manifold where the Wiper Vacuum Connects.
In doing so I got right about 19-20 Hg on the Gauge :)
...it seemed to stay steady there
If I rev up the engine should the reading drop, climb or just stay steady ?? This is during REv, figure it should even back out once at a Steady RPM.
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First it will drop, then increase, and return to a steady reading somewhere between the two extremes. A vacuum gauge is a valuable diagnostic tool. Most repair manuals (Motor's) ect, and such, show many readings and what each means.  
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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First it will drop, then increase, and return to a steady reading somewhere between the two extremes. That is Exactly what it did, I figured it would fluctuate under acceleration. Your vacuum reading is perfect. Great, that is a good thing to know, as well as all 6 Cylinders having the same Compression readings. Getting it closer to running SMOOTH...
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