Are my Racor vacuum gauges supposed to return to 0 when the engines are off?
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Are my Racor vacuum gauges supposed to return to 0 when the engines are off?
The gage should return to near zero, the drag needle if you have one, will show the highest vacuum that existed. You have to reset it by hand.Quote:
Originally Posted by finatic
Bobk
Just had some experience with this checking for air leaks. On my boat, I shutoff fuel at idle and then shut off engine when I reached about 10" of Hg. The vacuum held steady for 5 mins. until I opened the fuel supply. So, the values should return to zero unless there is a serious obstruction in the fuel system.Quote:
Originally Posted by bobk
If they are liquid filled you may need to pull the pin or plug on top of the case to vent the housing. You can get false readings if the inside of the housing is not at atmospheric pressure.
In most cases, the vacuum will hold at couple of inches, when it doesn't the check ball or it's seat, both come with overhaul kit RM1114-04, may/ likely have a problem.
My Racors are mounted several feet above the top of the fuel tanks so there is a built-in vacuum of 4-5 inches due to this constant lift. I hear this suction break when I crack the lids to change filters but I have not thought to check the gauge to see if it resets to zero.
Always crack the lid before trying to drain the bowl or else the gulp of air through the bottom drain stirs up the dirt and you will waste a lot more fuel cleaning this out. Don't forget to keep a bottle of clean fuel on hand to replace what was drained out.