question on vent

freddyray21

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Jun 10, 2006
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1949 Evinrude 3.3 Sportwin. The gas tank has the original cap which to me does not appear to be vented. There is a vent tube on the port side of the motor. It is connected to a metal line at the tank and to a nipple on the carb. The carb has a mechanism where you turn the high speed mixture and it takes a rubber pad off of the vent nipple on the carb thus opening the vent. That is how I see it. The question is that unless this mechanism is left open the tank will not vent. At least that is how I see it. I have the motor running and pumping water well. I need to check the carb to see if there is some crud in it that I missed, but it occured to me maybe I don't have the vent right also.
 

freddyray21

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Re: question on vent

already been there and am a member. Thought I would post in both as some members there read this board also.
 

1946Zephyr

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Re: question on vent

Freddyray!! Congradulations! Good to hear that you got that bugger goin'. My 1946 Zephyr has a vent tub set up like what you're describing. I can't exactly remember how it functions, though. I do believe however, that the main concept is to prevent gas from spilling when you detach the motor and lay it down, because the twist knob on the caps will. I think I will fire up my old Zephyr this weekend and see just what that vent tube does and how it works.
 

freddyray21

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Re: question on vent

I have found that I need to have the knob on the high speed valve for it to function correctly as the cam that activates it is on the knob. I never put the knobs on the needle valves until I get them adjusted out. I will just unhook the vent for now so it's always open until I get it adjusted.
 
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