Husky 346 rebuild problem for a newbie...

[a. palmer jr.]

I just replace the Carbs of two strokes engines not really interested in rebuilding a carb only complete motor heads really understand. I’m not knocking rebuilding carbs go for it but replacement is easier. D

...and cheaper if you buy knock-offs.

 

[Mike Gudgeon]

All the saws I've seen have a tank vent, some, like the Husqvarna, is in a non-traditional place, like horizontally in the area above the handle, still a vent though..

That's what I thought until I called Husq. Motor Australia (service) and talked with a fella, Matt I think, who told me that is not the case.
Apparently some have no breather and so the fuel line remains pressurised. I think the reason is so that a saw will still run even if the impulse passage or flap pump are weak or failing.

 

[a. palmer jr.]

That's what I thought until I called Husq. Motor Australia (service) and talked with a fella, Matt I think, who told me that is not the case.
Apparently some have no breather and so the fuel line remains pressurised. I think the reason is so that a saw will still run even if the impulse passage or flap pump are weak or failing.

So, what do they do when the saw is cold and runs for a short while, just keep restarting it until it warms up?

 

[huskihl]

That's what I thought until I called Husq. Motor Australia (service) and talked with a fella, Matt I think, who told me that is not the case.
Apparently some have no breather and so the fuel line remains pressurised. I think the reason is so that a saw will still run even if the impulse passage or flap pump are weak or failing.

They still have a breather but due to epa regs, newer models can only breathe in, not out

 

[a. palmer jr.]

They still have a breather but due to epa regs, newer models can only breathe in, not out

Sounds like the EPA is going a little overboard, they must not have much to do...

 

[Mike Gudgeon]

So, what do they do when the saw is cold and runs for a short while, just keep restarting it until it warms up?

It doesn't take much at all to pressurise the tank. Just a little movement will do it.

 

[larrypac]

Picking this back up- I rigged a pressure test for the carb using a blood pressure cuff. I pressured to 5 psi and it lost the equivalent of 1 psi in a little bit over a minute- is that acceptable, or does it indicate a carb rebuild?

Thanks for the answers to date!

I am a cheapskate and did not want to spend $20-$30 on a tester for my carb. I read your post and remembered that I have a blood pressure tester that I don't use anymore since my wife got a nicer one. Any tricks to the job? Brilliant, BTW!

 

[9050lx]

Pressurr on gauge may be in mm/hg which is much lower,i believe.

 

[a. palmer jr.]

That's what I thought until I called Husq. Motor Australia (service) and talked with a fella, Matt I think, who told me that is not the case.
Apparently some have no breather and so the fuel line remains pressurised. I think the reason is so that a saw will still run even if the impulse passage or flap pump are weak or failing.

The vent is not to prevent pressure in the tank of line, it is to prevent a vaccuum in the tank, keeping fuel from flowing into the carb. I'm thinking that all tanks have a vent, some are just hard to find.

 

[a. palmer jr.]

I am a cheapskate and did not want to spend $20-$30 on a tester for my carb. I read your post and remembered that I have a blood pressure tester that I don't use anymore since my wife got a nicer one. Any tricks to the job? Brilliant, BTW!

Just go down to probably any automotive store and pick up a tee fitting for the size line you're using and get a cheap pressure/vaccuum gauge. Tee the gauge into the line, bulb on the end and you have a pressure gauge. I was told but haven't tried that you can remove the bulb and suck on the hose and you can use the reading as a vaccuum. I was told that we can generate enough suction to test a saw (7 hg.) Don't quote me on that..

 

[huskihl]

That's what I thought until I called Husq. Motor Australia (service) and talked with a fella, Matt I think, who told me that is not the case.
Apparently some have no breather and so the fuel line remains pressurised. I think the reason is so that a saw will still run even if the impulse passage or flap pump are weak or failing.

They all have vents, otherwise air couldn’t get into the tank to replace fuel as it used. In the last 15–20 years or so, tank vents aren’t allowed to vent out into the atmosphere, courtesy of the EPA. The result is that tanks become pressurized due to the fuel in the tank trying to evaporate as it’s shaken or warmed up, which in turn may allow them to run without impulse.

 

[rupedoggy]

Did you guys notice you jumped from Feb. 1 2022 to today?

 

[huskihl]

Did you guys notice you jumped from Feb. 1 2022 to today?

It happens. I blame boredom

 

[a. palmer jr.]

Many of us still get older chainsaws to work on. Some of the older posts come in handy when we come upon a problem and we can't remember what the answer was.