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My carb exhales

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Nelson

Nelson

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For some time now I've been having a problem setting up my SU's. Now I've found that with my hand in front of the rear carb there is a light mist that hits my hand coming out of the carb. When I pulled the plugs the result is puzzling. The plugs for the first three cylinders are all the same dark color. For cylinder four the plug is much lighter in color and more of a reddish tan color. A pressure check has the first three cylinders very close together and number four is about ten pounds lower. In cylinder four, the pressure had not dropped after several minutes when I disconnected it. I'm at a loss to explain why that carb could be exhaling.
 
Nelson
That (the mist) is not abnormal, David Vizard speaks of it in normal use so I wouldn't worry about it.
Have you checked that your valves (particularly #4) are set to the proper gap lately? Could be an issue.
BillM
 
Just checked all the valve clearances and they were all within a thou of correct and now they are all spot on. I wonder what causes the mist but since Vizard talks about it I won't be concerned. Thanks.
 
Intake pulse from the valves closing. Like when you slam a door. Overlap timing has something to do with it as well.
 
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