Husqvarna 350 will not start

[Morgan1936]

My 350 has been running well but suddenly cut out and would not restart.

A good spark, good compression 125 lbs in2. Fuel not being drawn into the carburettor.

Replaced the carburettor but still not drawing fuel.  New fuel lines and tank filter,  It starts OK with an injection of easy start .

It seems as though there is no vacuum from the cylinder getting through to the carburettor. I have checked that the input gaskets are not blocking the inlet port.

 

Any ideas?

 

Thanks Paul

Edited May 8, 2020 by Morgan1936

[ChrisNewport]

Does it just fire on easy start or does it continue running? I would say 125 psi is on the low side and would cause starting and running problems.

[Stubby]

3 hours ago, Morgan1936 said:

My 350 has been running well but suddenly cut out and would not restart.

A good spark, good compression 125 lbs in2. Fuel not being drawn into the carburettor.

Replaced the carburettor but still not drawing fuel.  New fuel lines and tank filter,  It starts OK with an injection of easy start .

It seems as though there is no vacuum from the cylinder getting through to the carburettor. I have checked that the input gaskets are not blocking the inlet port.

 

Any ideas?

 

Thanks Paul

As Chris above says . I think you should have around 135 psi minimum . This is with the dished piston . You can get more if you fit a flat top piston from a 353 .

Edited May 8, 2020 by Stubby

[Morgan1936]

Thanks for your replies.

It only runs for a short burst on easy start just for a few seconds.

It was running just fine on 125lbs/in2 and  has been for several weeks.

No fuel is being sucked up from the tank, all fuel lines are free.

 

[spudulike]

Why measure the compression in that way where everyone else will give it one to see what sort of initial compression a saw has - 70psi+ is normal then 5-6 to give max compression 150-170 is typical with 170 on a nice engine.

Sounds like a top end issue to me but can't be sure as you may not have used a known decent OEM carb.

[spudulike]

"Input Gaskets"......are you sure it is a 350??? There are no input gaskets!!!!

[Morgan1936]

Thanks Spudulike,

You are correct no input gasket. It is a 350.

My confusion arose as I recently fettled a  very old ( 35 years) Sachs Dolmar 113, it needed new carb parts. That did have an input gasket.

What struck me was the far superior (IMHO) construction of the old Sachs Dolmar, decent Duralamin where Husqvarna use plastic, even the crankcase on the 350 is plastic. Yes the 350 is much lighter but not half as durable as the old 113. I know which one will still be around in 10 years! The 350 is already showing signs of age with screw threads worn and cracked plastic.

[Stubby]

8 hours ago, Morgan1936 said:

 

What struck me was the far superior (IMHO) construction of the old Sachs Dolmar, decent Duralamin where Husqvarna use plastic, even the crankcase on the 350 is plastic. Yes the 350 is much lighter but not half as durable as the old 113. I know which one will still be around in 10 years! The 350 is already showing signs of age with screw threads worn and cracked plastic.

That is because it is not a " pro " saw .  If you had a 346 which is a pro version you would see the difference .

[Rough Hewn]

Impulse hose leaking?

[spudulike]

Just re read your compression figures - your "PS in 2" is "PSI" and not in two pulls as I thought you meant. 125 PSI is very low for one of these saws where a worn one will make 150 and a lightly used/reburbished one will make 170PSI.

You have seized your saw, take the exhaust off and you will be greeted by a scored piston!

The Dolmar 113 and 350 are different types of machine, one pro and one home owner. The 345/350 are actually pretty good machines despite there plastic parts. They can leak air around where the metal cylinder parts mate with the plastic but are nice to use.