Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Husqvarna => Topic started by: Gregg MacPherson on February 13, 2014, 03:39:18 pm


Title: Checking fuel vent on Husky 154
Post by: Gregg MacPherson on February 13, 2014, 03:39:18 pm
Hi,
I have an old 154 that I have kept going for nearly 20 years with very little real knowledge.  Just recently downloaded a service manual.  Reading on how to check the fuel vent with a pressure guage.  I don't have the things I need here yet to make the pressure test properly.  Is there a way I can check the vent function or perhaps clear the vent just with compressed air.

Cheers,
Gregg. 
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 03:56:13 pm
What makes you suspect the fuel vent OEM # 501 87 31-01 $4 at partstree.com? If the saw is 20 years or so old save yourself the expense and trouble; just replace it. About a 10 minute job!
Title: Re: Checking fuel vent on Husky 154
Post by: Gregg MacPherson on February 13, 2014, 04:14:24 pm
I'm hearing a whistling noise that lasts for two or three minutes after switching off.  Sometimes the engine quit and I don't think was getting fuel. 

I was just looking at new vents on eBay.   I'm in New Zealand and I have normally found it a bit slow and expensive finding new 154 parts locally.
Title: Re: Checking fuel vent on Husky 154
Post by: eriksat1 on February 13, 2014, 04:39:32 pm
On my 372xp the vent was getting iced up from the outside sawing in snow at zero temp outside. Anyway how the vent worked on mine there is a check valve at the gas tank that only lets air into the tank through the rubber hose, won't let air or gas out. So when I bring the saw inside and it warms up it builds pressure inside the tank because I can hear it escape when I open the gas cap. You can hardly tell if the check valve is plugged by blowing on the hose with your mouth, with gas cap off and tank empty. I think because of the small orifice in the check valve, But I could hear the air come through when I blew it with a air gun at a low pressure. If you can blow air back out the gas tank through the check valve the check valve is bad. Mine the hose where the vent air sucks from under the saw was getting iced up and acted like it was running out of gas after some hard cutting then wouldn't start again right away. I crack open the gas cap and all was good again for a while until the gas tank sucked itself into a vacuum again. It is a **** cutting in deep snow.
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 05:03:27 pm
That is helpful however the 154 does not use the same tank vent setup as the 372 in that it does not have the rubber hose as does your 372.  However it is late summer in New Zealand so I doubt that Gregg has a problem with cold weather operation. The same situation can occur with the 154 as did on your 372, if you can turn the saw on its' right side and fuel leaks out the vent probably lost the little white puck. If there is a vacuum in the tank then it is probably plugged with chips.

The 154 uses a pressed or screwed in vent tube with a piece of white plastic pressed into the exterior opening. See the attached picture, the vent is noted as part number 501 87 31-01. It is a common part used on lots of HVA saws and should not be difficult to find in New Zealand, Just get one for a Husqvarna 372 they are the same part..

It is in fact still used after a fashion on the latest saws ERIKSAT1 refers to (third attachment) as well as the original 372 saws (second attachment)
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 05:28:15 pm
Here is the correct vent on eBay:

http://www.ebay.com/itm/NEW-HUSQVARNA-FUEL-TANK-VENT-FITS-362-3120-372XP-385-394-51-55-501873101-L-K-/150935211729?pt=LH_DefaultDomain_0&hash=item2324708ed1

As far as the question in your original post, I looked at all the Workshop Manuals that I have close at hand and cannot find where the tank vent function is checked. I am not doubting you I just can't find that documented. If I am correct it may be quite hot in New Zealand this time of year, if left in the sun the fuel might be getting too warm in the tank and creating a problem.
Title: Re: Checking fuel vent on Husky 154
Post by: Gregg MacPherson on February 13, 2014, 05:53:39 pm
Thanks for giving it your attention.  I had a hard time finding a free download of the 154 service manual.  I seems like a small industry is there,  finding and trying to monetize service manuals,  making it hard for one to find those freely available.  Placing obstacles in the way.  I'm hopiung that if I search your forum I will find people who have posted these manuals so that they are freely available.  No-one should pay for a service manual for a saw built in 1984 by Husqvarna.

On page 47 of the manual I have,  the tank pressure test is covered.  On page 48 the vent replacement is covered.  It may be just me that connects these two.  Pressure in the tank may not show much about the vent.  Perhaps one needs a vacume in the tank for that?

I'm a learner.  It's fun sofar.
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 05:59:28 pm
Gregg post a request to the ipl and service manuals thread here:

http://chainsawrepair.createaforum.com/ipl-and-service-manuals/

For the manuals you need and someone will be along and e-mail you one. In fact I will post a request as I am curious as to what you are reading. Is the manual you have specific to the 154 or is it one that covers a whole bunch of saws?
Title: Re: Checking fuel vent on Husky 154
Post by: Gregg MacPherson on February 13, 2014, 06:16:48 pm
It's titled on the page as  "Workshop manual chain saw model 154/254" .  If I can,  I will upload to you.  It's 7.9Mb.

I just tried attaching that.  My upload may not have worked.  I watched something head upstream,  but my post seemed to bog down after (I thought) that had completed.
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 06:32:52 pm
Gregg, send the manual here
Rochusqvarna@rochester.rr.com
Title: Re: Checking fuel vent on Husky 154
Post by: Grande Dog on February 13, 2014, 06:35:49 pm
     Howdy,

   A good shade-tree way to check it is to fill the tank with fuel, replace the cap, lay the saw on it's side, disconnect the fuel line. The fuel should flow a constant steady stream. If it slows down, you have issues.

Regards
Gregg
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 08:37:43 pm
OK, got the manual, all they are telling you to do is to put pressure into the tank (50kPA) with a pump and that should reduce to 20kPa within 60 seconds. What Gregg suggests above should accomplish the same thing.
Title: Re: Checking fuel vent on Husky 154
Post by: KilliansRedLeo on February 13, 2014, 09:28:19 pm
Here is the least cost method to do what the manual says. Buy a used blood pressure cuff, disconnect the tubes from the cuff keeping only the bulb, the tube leading to the gauge and the other tube. Hook the tube out of the gauge up to your fuel line and put the pressure into the tank, then watch the pressure go down according to the HVA specs.
Title: Re: Checking fuel vent on Husky 154
Post by: Gregg MacPherson on February 13, 2014, 09:52:35 pm
Sounds like a good tip.  Cheers.
Title: Re: Checking fuel vent on Husky 154
Post by: Gregg MacPherson on December 01, 2015, 05:46:32 am
That 154 is still going strong.  Only complaint is that if it stalls or runs out of gas while hot it really hard to start hot.  Looking at the plug while trying to start hot,  sometimes it looks wet,  so I thought I had flooded it somehow.  Spark is strong.

In its early semi-retirement this 154 joins the anual Silverdale firewood posse.  Seen here perched between the Stihls.  Very sentimental of me I know.