Gas Tank Vent; Open or Closed?

[TampaBoater]

This very well may be one of those stupid questions no one has heard in a while, but since I am new to the boating world, and you guys are very informative and kind, here goes.

Should the vent on the gas tank (6 gal premixed) be closed or open while running the boat?

Thanks.

 

[mercuk]

Re: Gas Tank Vent; Open or Closed?

This very well may be one of those stupid questions no one has heard in a while, but since I am new to the boating world, and you guys are very informative and kind, here goes.

Should the vent on the gas tank (6 gal premixed) be closed or open while running the boat?

Thanks.

Gota be OPEN!

If not your engine will probably shut down after a few mins.

 

[jasoutside]

Re: Gas Tank Vent; Open or Closed?

OPEN!

What do I win?

Edit: Never mind, mercuk beat me to it.....

 

[TampaBoater]

Re: Gas Tank Vent; Open or Closed?

Gota be OPEN!

If not your engine will probably shut down after a few mins.

So this is probably why me engine bogs down soon after I increse throttle? Compression is good, sparks are good, fuel system is good. That's gotta be it.

 

[Texasmark]

Re: Gas Tank Vent; Open or Closed?

So this is probably why me engine bogs down soon after I increse throttle? Compression is good, sparks are good, fuel system is good. That's gotta be it.

Your fuel pump is a vacuum source and is sucking on the tank. With no way to replace the volume in the tank that the fuel occupied (vent closed) tank goes into the vacuum state also. The more vac in the tank, the less effect the fuel pump vac has to suck fuel. Finally an equilibrium is reached and it just quits as does your engine.

Mark

 

[TampaBoater]

Re: Gas Tank Vent; Open or Closed?

Your fuel pump is a vacuum source and is sucking on the tank. With no way to replace the volume in the tank that the fuel occupied (vent closed) tank goes into the vacuum state also. The more vac in the tank, the less effect the fuel pump vac has to suck fuel. Finally an equilibrium is reached and it just quits as does your engine.

Mark

Wow..thanks for the eye opener TexasMark….

 

[michaeljbaker55]

How far open should the vent be on the fuel tank cap?