Ms 310 shooting gas out of breather hose help

[Billy Ray]

hey guys I’m new to the forum. I just got a ms 310 second hand and it was missing the breather hose on the gas tank.so I went to my dealer and bought one.I moved one of the little grub screws by screwing it in didn’t know you weren’t supposed to so not sure if that’s my problem? I started it up reved it up and saw the line that goes from the tank to the carb leaking. so back to the dealer I went. I bought a new fuel tank line that goes from the tank to the carb. but it’s blowing gas out the top of the little breather line when I rev it.not sure what’s wrong? I opened up the exhaust yesterday and tuned the carb with a tach not sure that that would make a difference though ?thanks for the help in advance.

 

[Billy Ray]

Air bubbles out as well even after I shut it off

 

[Billy Ray]

Saw runs and idles fine

 

[HarleyT]

Can you take a pic of the lines?

 

[buzz sawyer]

Welcome to the site. Can you add some punctuation to your first post to make it a little more understandable? Like Harley said.,some pics of the lines in question may help.

 

[Billy Ray]

Can you take a pic of the lines?

Here’s the lines the breather and the Line to the tank are both new.but I did screw the screw in the vent line didn’t know I wasn’t supposed to. The line in question is the top fuel and air bubbles come out of there.

 

[Billy Ray]

Welcome to the site. Can you add some punctuation to your first post to make it a little more understandable? Like Harley said.,some pics of the lines in question may help.

I’m sorry my apologies I fixed it the best I could here’s the line

 

[buzz sawyer]

What is a grub screw? The screw in the vent line allows air in past the threads to keep the pressure neutral as fuel is drawn from the tank.
Sounds like it's building up pressure in the tank somehow. Maybe getting hot when it's running and tank pressure is building up? How long does it have to run before the gas starts coming out?

 

[Billy Ray]

What is a grub screw? The screw in the vent line allows air in past the threads to keep the pressure neutral as fuel is drawn from the tank.
Sounds like it's building up pressure in the tank somehow. Maybe getting hot when it's running and tank pressure is building up? How long does it have to run before the gas starts coming out?

Yes the two little screws in the vent line.As soon as you start it and rev it up it comes out

 

[Billy Ray]

Yes the two little screws in the vent line.As soon as you start it and rev it up it comes out

The more I depress the throttle the more pushes out.

 

[HarleyT]

You need the proper vent setup.

 

[Billy Ray]

You need the proper vent setup.

Is that not the proper vent?its what the dealer gave me

 

[HarleyT]

Here is what one looks like, the screws are too tight to let fuel squirt out.

 

[Billy Ray]

Here is what one looks like, the screws are too tight to let fuel squirt out.

View attachment 736820

That’s like mine it’s just a black hose

 

[Billy Ray]

Here is what one looks like, the screws are too tight to let fuel squirt out.

View attachment 736820

I will order one

 

[Billy Ray]

Here is what one looks like, the screws are too tight to let fuel squirt out.

View attachment 736820

I ordered one off eBay hopefully it’ll work better than the stihl

 

[SteveSr]

I ordered one off eBay hopefully it’ll work better than the stihl

These are the old style tank vent C.A. early 90's. They are designed to pass vapor out and air in. If the gas level is high or the saw is turned over they may leak gas out.

Bigger question is how a 2000+ EPA saw (flippy caps) still have this old tank vent on it. Well, according to my IPL it isn't supposed to. This one has a remote tank vent just like the MS250s series.

The correct tank vent is located remotely in the same rubber grommet that fits over the carb adjusting screws. Odds are that the tank vent is still there but the hose is gone or rotted away. Unfortunately, your photo doesn't show the carb screw grommet. The hose is also supposed to go inside the orange housing up and over the carb. I think it is just standard 3.1x5.7mm Stihl fuel line.

 

[Billy Ray]

These are the old style tank vent C.A. early 90's. They are designed to pass vapor out and air in. If the gas level is high or the saw is turned over they may leak gas out.

Bigger question is how a 2000+ EPA saw (flippy caps) still have this old tank vent on it. Well, according to my IPL it isn't supposed to. This one has a remote tank vent just like the MS250s series.

The correct tank vent is located remotely in the same rubber grommet that fits over the carb adjusting screws. Odds are that the tank vent is still there but the hose is gone or rotted away. Unfortunately, your photo doesn't show the carb screw grommet. The hose is also supposed to go inside the orange housing up and over the carb. I think it is just standard 3.1x5.7mm Stihl fuel line.

It doesn’t have the grommet but I ordered everything to put the new style on it including the grommet