Chainsaw Repair

How To Basics - Carb Fixes + Mods - IPL and Service Manuals => How To Basics and Fixes => Topic started by: aclarke on October 26, 2015, 11:07:22 pm

Title: improving Grubb screw type vents
Post by: aclarke on October 26, 2015, 11:07:22 pm
[img http://(http://i1184.photobucket.com/albums/z329/Aclarke123/Mobile%20Uploads/20151026_190418_zpshkwxueyf.jpg) (http://s1184.photobucket.com/user/Aclarke123/media/Mobile%20Uploads/20151026_190418_zpshkwxueyf.jpg.html)/img]

Trying to figure out a no leak tank vent to retrofit the older grub screw type on older saws. Found a R/C valve that works for a while then the gas eats the flapper material.  Anyone know of a similar sized check valve that's gas proof??


(http://)
Title: Re: improving Grubb screw type vents
Post by: 3000 FPS on October 26, 2015, 11:54:56 pm
The only other ones I know of are the ones I see on the Echo and Shindiawa weed trimmers.
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 27, 2015, 09:47:19 am
Thanks, I'll take a look at them
Title: Re: improving Grubb screw type vents
Post by: srcarr52 on October 27, 2015, 10:12:55 am
Shouldn't there be a flapper check valve pulled into the tank? All you need on the line is something to keep debris out.
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 27, 2015, 12:04:01 pm
Shawn, I'll check. This one had two grub screws in it
Title: Re: improving Grubb screw type vents
Post by: srcarr52 on October 27, 2015, 02:05:42 pm
Some stihl models should be a rubber umbrella flapper inside the tank with the tit pulled into the breather boss area. They are the exact same umbrella flapper used in accelerator pumps in holley and edelbrock carbs. This keeps anything from leaving the tank, then the line has grub screws to keep the debris out.

(http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/clgAAOSwPcVV0QL2/$_35.JPG)
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 27, 2015, 02:28:57 pm
Yep, bought a couple dozen of those last month for about 50 cents each!!   Stihl was about $8.

 Not sure if this early 044 tank has one of the umbrella check valves like the later tanks.  I'll check tonight
Title: Re: improving Grubb screw type vents
Post by: dannyupsolate on October 27, 2015, 04:11:12 pm
echo type vents $1.89 at carbtech21
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 29, 2015, 12:15:51 pm
Shawn, saw IS set up for an umbrella vent but missing. Put a new one in!!  Nightmare to pull through as the tube is Sooooo small. Used small hemostats.

Carburetor umbrella and Stihl appear identical less the mfg markings
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 29, 2015, 12:17:01 pm
Stihl on right



[img http://(http://i1184.photobucket.com/albums/z329/Aclarke123/Mobile%20Uploads/20151028_174840_zpsw8ronktq.jpg) (http://s1184.photobucket.com/user/Aclarke123/media/Mobile%20Uploads/20151028_174840_zpsw8ronktq.jpg.html)/img]
Title: Re: improving Grubb screw type vents
Post by: srcarr52 on October 29, 2015, 01:59:04 pm
I think it's on this site that someone noticed it's the same as a Holley/Edelbrock/Carter/Motorcraft part. Made me blow the dust off my Holley track box in search of one for an 066, sure enough I had 3 in the box, I probably have another handful in the Holley box in our race trailer.

The marking is probably just a die number, same factory... different injection molding die.

Yes, they suck to get pulled through; but like many things, a little lube goes a long way.
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 29, 2015, 03:20:05 pm
I bought some a month or so ago for Carter/Edelbrock and posted about them on another thread.  Theyre identical specs as far as I measured. They tear as easy as the as the Stihl part too!! Lol
Title: Re: improving Grubb screw type vents
Post by: 660magnum on October 29, 2015, 07:30:59 pm
[img http://(http://i1184.photobucket.com/albums/z329/Aclarke123/Mobile%20Uploads/20151026_190418_zpshkwxueyf.jpg) (http://s1184.photobucket.com/user/Aclarke123/media/Mobile%20Uploads/20151026_190418_zpshkwxueyf.jpg.html)/img]

Trying to figure out a no leak tank vent to retrofit the older grub screw type on older saws. Found a R/C valve that works for a while then the gas eats the flapper material.  Anyone know of a similar sized check valve that's gas proof??


(http://)

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXG869&P=7
Title: Re: improving Grubb screw type vents
Post by: Cut4fun . on October 29, 2015, 08:04:13 pm
[img http://(http://i1184.photobucket.com/albums/z329/Aclarke123/Mobile%20Uploads/20151026_190418_zpshkwxueyf.jpg) (http://s1184.photobucket.com/user/Aclarke123/media/Mobile%20Uploads/20151026_190418_zpshkwxueyf.jpg.html)/img]

Trying to figure out a no leak tank vent to retrofit the older grub screw type on older saws. Found a R/C valve that works for a while then the gas eats the flapper material.  Anyone know of a similar sized check valve that's gas proof??




http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXG869&P=7

Nice find Jim

NOTES FROM OUR TECH DEPARTMENT
This Gasoline Check Valve by Formost is Designed for use between the Fuel
Pump and Muffler. It helps to Prevent Back Flow From Muffler Pressure and
Keep the Residual Glow Fuel and Oil from Flowing Back Into the Pump.

INCLUDES

One Check Valve (blue and white)

SPECIFICATIONS

Size: 1/16" Inside Diameter: 1.6mm

FEATURES

The check valve may be used in any application that requires a
one-way valve.
Made from fuel proof nylon.
May be used with GAS, KEROSENE, SMOKE OIL, DIESEL, and GLOW fuel.
May be used in smoke systems and fuel systems requiring the
maintenance of tank pressure.
Direction of flow is to the BLUE END.
Has a stainless steel ball bearing sealing member that makes an
adequate (but not extremely tight) seal.

(http://www2.gpmd.com/image/f/forq2050.jpg)

Title: Re: improving Grubb screw type vents
Post by: Cut4fun . on October 29, 2015, 08:07:12 pm
I think it's on this site that someone noticed it's the same as a Holley/Edelbrock/Carter/Motorcraft part. Made me blow the dust off my Holley track box in search of one for an 066, sure enough I had 3 in the box, I probably have another handful in the Holley box in our race trailer.

The marking is probably just a die number, same factory... different injection molding die.

Yes, they suck to get pulled through; but like many things, a little lube goes a long way.
I bought some a month or so ago for Carter/Edelbrock and posted about them on another thread.  Theyre identical specs as far as I measured. They tear as easy as the as the Stihl part too!! Lol

Thread in stihl board http://chainsawrepair.createaforum.com/stihl/stihl-tank-vent-check-valve/
Title: Re: improving Grubb screw type vents
Post by: 3000 FPS on October 29, 2015, 09:50:57 pm
Excellent Jim I did not know such a thing existed that small.   Sounds like it will work well on a chain saw.

I wonder how it would do on the Poulan micro series saws with the long fuel lines.   It might help keep the fuel in the line.
Title: Re: improving Grubb screw type vents
Post by: aclarke on October 29, 2015, 11:23:31 pm
Jim, thanks.  Looked online for a long time and missed those.  Sullivan makes a nice check valve but couldn't find any data on fuel compatibility. Echo, shindaiwa look good too...
Title: Re: improving Grubb screw type vents
Post by: 660magnum on October 30, 2015, 08:26:24 am
The Sullivan one is intended for "smoke" oil. It is kerosene and petroleum oil compatible. It has an aluminum case.

Don't know about ethanol?