1989 metal gas tank vent concern

[8914ft40]

How does a 1989 6 gallon metal Yamaha tank vent? New cap from boats net has no vent screw, does anybody know? Thanks

[boscoe99]

What part number did you buy? It appears to be 6Y1-24610-00-00.

According to data at boats.net the tank and cap are auto venting. You may be thinking of a much older style cap that has a vent screw that could be loosened and tightened.

Thanks to the EPA, and too many boaters in the USA today, the fuel system world has been turned upside down. Be glad that you did not have to throw away your old tank and go to the completely new sealed system.

[8914ft40]

Gas tank vent

Thanks for the reply, I seen where it is supposed to be auto venting but Im not sure just how it is supposed to vent with no vent screw on the cap, the parts diagram shows a vent screw on top of the cap.

[boscoe99]

What diagram are you looking at? More than likely it is an illustration of the original cap that had a manually vent screw. A replacement cap of a different configuration will normally not be shown.

Yamaha does not update their data to show later configurations.

Remove the new cap and inspect it from the underside. You might see something that shows how the auto vent mechanism works. Usually there are check valves and such that will allow air to enter the tank but prevent fuel fumes within the tank from getting back out, under normal pressures.

[robert graham]

The new EPA approved tanks/caps vent only in, not out....keeps gas fumes from leaking out into atmosphere. Some folks just leave their caps slightly cracked open to allow tank and system to breath. The build up of pressure in the new fuel systems has been known to damage certain parts and seals in the fuel systems....I've always kept my fuel tank full with cap loosened slightly to prevent pressure build up....please don't tell the EPA guys that I forgot to tighten my gas cap!