064 leaks fuel from carb just sitting

[pcrevelli]

The fuel pours out of the vent holes on the bottom of the Walbro HJ6A. If I relieve the pressure from the tank by cracking the cap open, it will stop. Through searching here, some say if there is dirt in the needle & seat, that will cause this. I have checked/cleaned that, and replaced both diaphragms in the carb to no avail.
This started after replacing the tank assy. I did not have the issue before, but also noticed after replacing the tank, the orange rubber tank vent "valve" was missing in the old tank, letting the tank depressurize when sitting. This is a newer saw to me, and I store them empty, so the condition may have existed before.
Prior to the change, the saw ran perfect, now it runs rich at idle and floods out (go figure), but revs out fine. This has become one of my favorite saws. .
What direction would you suggest I start looking?
Thanks in advance.

 

[treeslayer2003]

bump

 

[Bilge Rat LT 20]

Those vents are for air only.
Check the gaskets/diaphragms for proper install. Make sure they are the right ones too.
It is flooding so it is not regulating fuel/leaking internally properly.
The wrong diaphragm or gasket in wrong location can cause this.

 

[Deets066]

I had this problem with an 034, switched tank and it was real hard starting and the carb would leak fuel. At first I thought tank vent. So I put a new one in and that didn't help any. The starting problem was because the master control was rubbing and would not go all the way to full choke.

With the fuel leaking, I ordered a rebuild kit and will see if that helps. It only leaks sometimes just after you run it a while then let it sit, if I release the pressure by opening the cap it doesn't leak.

 

[blsnelling]

There should be no holes in that cover, if I'm seeing it right.

 

[treeslayer2003]

There should be no holes in that cover, if I'm seeing it right.

thats what i thought.........but thought i'd wait for some one who knows lol.

 

[blsnelling]

It's the other side that has the vent hole.

 

[Bilge Rat LT 20]

Yep the metering side of the carb has the vent.
Looks like the tan/clear diaphragm on the carb.

 

[super3]

Those holes are standard on that carb.

 

[pcrevelli]

Both top and bottom covers on the carb have the vent holes. I have been looking at the IPL, but I can't tell from the illustration if the holes are there.

 

[Mad Professor]

He's pointing at the bottom carb cover, the pump side. You can see parts 23, 24 and 27 of the carb IPL on the side

1. 23 1110 122 9300 Clip
2. 24 1106 122 7400 Round head screw
   27 1117 122 9000 E-clip
   
   The E-clip and clip hold the choke and throttle shafts, respectively.

With orientation sorted out..........

The pump diaphragm looks installed O.K. (note nub of material sticking out), however I don't see the nub of the corresponding pump gasket.

Unless it's an AM gasket with no nub, I'll go with the pump gasket is not installed correctly.

Was carb worked on when you installed new handle, or after?

 

[pcrevelli]

The carb was not touched till after the leak problem surfaced, which was after the handle was replaced, with the in-tact tank vent valve. The carb kit used is a Walbro kit. There are two allignment pins on the gasket with corresponding holes in the gasket to prevent misallignment, but I will double check that. Part of what is so baffling, is how fuel is getting past the the diaphram/gasket.

 

[pcrevelli]

Thanks so far...

 

[pcrevelli]

The picture is of the bottom of the carb. Because of the lighting, I had to tip the saw up, to get the shot without shadowing.

 

[Adirondackstihl]

Worn needle & or weak pop off pressure.

But I also seem to think your diaphragm is orientated incorrectly. I can't recall ever seeing the pump diaphragm locating tab off the side of the carb. Usually off the front or back......but Im not 100%

 

[LegDeLimber]

Did you match ALL of the kit parts with the old ones?
Always lay the old and new ones on top of each other
and then look at them from both sides.
You want to look for any material showing that even slightly blocks any holes.
any changes can influence the fuel charctoristics.

If a flap is turned in a different direction, ask what will it affect.
will it still operate without hitting a cover or some other part
or snag on the gasket, etc.
is the pivot point now in the way of the (normal) flow dircetion of the fuel?
if so, ask yourself will it try to fold or be slow to reclose after each pulse
or do some other bizzare thing.

Guys, I know it sounds simple, but look at the long thread at that mispalced
vent hole issue, in the Walbro 199 carbs and ask why people didnt see it.

Edit: fixed a couple of my worst typos.
And absolutly needed to mention that it was Tree Monkey (thank you), who enlightened so many of the masses.
a bit tough though, to pick a thread that covers it well yet had the least "distractions"

 

[Mad Professor]

Worn needle & or weak pop off pressure.

But I also seem to think your diaphragm is orientated incorrectly. I can't recall ever seeing the pump diaphragm locating tab off the side of the carb. Usually off the front or back......but Im not 100%

IPL shows diaphragm and gasket tabs where diaphragm tab is now.

I don't see the gasket tab?

 

[Mad Professor]

Picture of the OEM kit parts here:

http://www.ereplacementparts.com/new-repair-kit-p-835607.html

 

[pcrevelli]

I will definitely check the orientation of the gasket again.

 

[pcrevelli]

The gasket was on backwards/upside down. As mentioned by LegDelimber, AdirondakStihl, and Mad Professor, the tab of the diaphragm and gasket need to align. The saw runs perfect once again.....
Thanks to everyone who offered suggestions, and gave me something to think about....Here is a picture of it reassembled correctly.