MS 290 Farm Boss

I too agree, no doubt fuel builds pressure when heated, but I’ve never heard of increased throttle making fuel leak out more.
Husky doesn’t use that style vent so my experience was only 2 times on 2 different Stihls (that were for flipping ). I replaced both.

 

The only time I might think it would maybe leak more is on a full tank. Vibration causing the fuel to be shaken around in the tank when it is full and closer to the vent. The reason I think of this is I have a gas hedge trimmer that had a dried out grommet for the fuel line , this was at the top of the tank. If I ran it on a half tank it would leak a tiny bit , if I filled the tank it would leak way worse. OK at idle but when trimming it wasn’t happy. I’m sure tank pressure did not exist in this case.

 

Is it possible that it is pushed in the tank to far ?
Just guessing, never saw a screw as a vent.

 

I'd be surprised if you don't have a saw with a grub screw vent...

 

This whole grub screw thing to me is a cheezie way out. Maybe if the vent was taken from filtered air after the air filter then maybe ok. Otherwise it is unfiltered air in a dusty environment getting sucked into the tank , yeah I know it is not a lot of air but over time I would think it would start clogging up.
Sure something like a carb on a car engine has air bleeds in the carb but these are after the air filter so they are breathing filtered air.

This is just me thinking out loud so take it for what it is worth.
To me this is just a hack job for a vent. No filter and no one way check valve.
Agree or disagree I would be ripping it out and installing something different.

 

It doesn't push into the tank, the vent tube slides onto a nipple on top of the tank. I did notice that it didn't seem to leak fuel as bad or at all as the fuel level decreased, but after installing the grub screw vent tube and running the saw it is definitely pushing fuel out the top of the vent tube around the screw, so I don't think vibration alone could do that.

 

I do plan on going with the OEM vent and vent tube but as of right now I can't find one anywhere. The only place I could even find one listed is here Stihl 029 039 Ms 290 390 310 Vent With Hose New Oem 00003505802, 11273587600
and they are listed as out of stock.

 

Meh...no big deal IMO...almost every carbureted motorcycle (dirtbike/ATV) ever made has an unfiltered/vented carb and tank...

 

Flash back to my old dirt bike with the tube straight up out of the filler cap to the triple clamp.

 

Maybe your fuel line is leaking?

 

No, I've watched the fuel spit out the vent tube nipple and around the grub screw in the new vent tube.

 

Just get a Husky?

 

I get what you're saying but I'd wager way more junk gets in the tank from people not cleaning off the cap and surrounding area before filling it.

 

Probably..... memory's going downhill.
Can't remember if I even had lunch......

 

I can help...I know you had lunch Brotha!!

 

Hey, a big block needs lots of fuel, right?!

 

Can confirm

 

update: Finally got an OEM vent tube and vent on it...works like a charm, no fuel leakage at all like I was having with the grub screw vent tube.

 

So what type of vent is it?