Stihl 039 venting gas

[DaveinGlengarry]

I see in 2010 Nethercutt had this issue and a new gas line fixed his problem. Unfortunately, it didn't work for me... My inherited 039 ran fine for 2 years, then developed the issue of venting fuel out the tank at high rpm. I've changed the vent line, fuel line and installed a new carb kit (gaskets, diaphragm, needle, spring, etc). No change. I've searched all over, but no joy, yet. Has anyone had this issue and figured it out...? If I've missed a thread, please let me know...? Thanks in advance.

 

[Wood Doctor]

Even though you changed the vent line, the port coming up from the tank could be clogged. Remove the vent line and drop a stiff wire down that port that connects to the line to be sure that it is not obstructed. That might do it.

 

[DaveinGlengarry]

Even though you changed the vent line, the port coming up from the tank could be clogged. Remove the vent line and drop a stiff wire down that port that connects to the line to be sure that it is not obstructed. That might do it.

It's not clogged, unfortunately. That's where the tank is venting fuel from. When the line is on, it vents fuel until the pressure is enough to pop the line off. Then, of course, the fuel almost pours out of the vent nipple. At idle, the pressure seems to be decreased, but then the saw stalls. I can cut lots of wood, as long as I don't mind wearing half the fuel in the tank...

 

[HarleyT]

Show us a pic of your vent line.

 

[DaveinGlengarry]

Show us a pic of your vent line.

 

[HarleyT]

What is the deal with the end of the line?
Was this the end on the nipple with the damage?
Take a razor knofe and cut it square and try it again.

 

[HarleyT]

The saw stalling, well,
show us some good pics of your fuel line........

 

[DaveinGlengarry]

What is the deal with the end of the line?
Was this the end on the nipple with the damage?
Take a razor knofe and cut it square and try it again.
View attachment 738518

I did square it off before I put it back on. It's venting through the screw in the end of the vent line, which it's not supposed to be able to do at all (my understanding is the screw has enough of a gap to let air out, but not gas - but, the gas does make it through for a few seconds before popping the line off). Apparently there's a fair bit of pressure. The fuel line is brand new yesterday. When I get out to the shed, I can take a pic, but it's in mint condition.

 

[HarleyT]

So it is just a made up deal? Go to the Stihl dealer, and buy the actual vent #1117 350 5800, it has 2 inserts, in serious
hard tight line.

 

[DaveinGlengarry]

So it is just a made up deal? Go to the Stihl dealer, and buy the actual vent #1117 350 5800, it has 2 inserts, in serious
hard tight line.

View attachment 738520

That's the one. This one's black, but same part number, 2 screws.

 

[HarleyT]

Did it come in any wrapper with that part number?

Or did the Stihl guy just "make" one? I worked at a dealership that did that.
How much did they charge you?

 

[HarleyT]

Wow!!!
I can see them doing that!!!


1117 350 5800 TANK VENT $12.88

 

[DaveinGlengarry]

Did it come in any wrapper with that part number?

Or did the Stihl guy just "make" one? I worked at a dealership that did that.
How much did they charge you?

Wow!!!
I can see them doing that!!!


1117 350 5800 TANK VENT $12.88

Yeah, that's about what I paid, but now that you mention it, he just handed it to me. Maybe I'll head back in to ask to see the packaging...

 

[HarleyT]

The black line is used on the newer style vent, but it is a lot more supple. I made a good vent using the new style and a piece of an old 021 fuel line.....
Been using the saw for @ a year or so with it.


Still not your stalling problem though....