Husky 55 Won't Run

[turkeyvulture]

I have a Husqvarna 55 (Classic, not Rancher) that will start and idle but bogs and quits when I open the throttle. Does this with 3 carburetors so far and new fuel filter and all possible adjustments on both mixture screws. I can blow through the fuel line so no restriction there. Tried various spark plug gaps. Good strong spark. About the only thing left is magneto/spark plug wire assembly but that seems unlikely. Gas is new.

Any help appreciated.

 

[RandyT]

Remove the screen in the carb and make sure it isn't plugged with carbon. If no screen then remove the carb and check the exhaust ports on the side of the cylinder for blockage. if no blockage there then start the saw without the muffler attached. If it runs fine there then install a new muffler because it is clogged internally.

 

[arrow]

Since you've put on 3 new carbs (I assume they were new), it is not a carb problem. The 55 is an old saw and if you never changed the fuel lines, this could easily happen. They develop minute perforations that draw in air. That is why you can blow through them. They aren't blocked but I bet they are porous if indeed they are the originals.
A clogged muffler is usually the result of a muffler screen carbon build up. The saw will run and at times can even accelerate, but as soon as it warms up, it stops in less than a minute. if it is dead plugged, then you will not accelerate.
Be sure to spray the muffler bolts with a Liquid Wrench type product before you try to loosen them and let it sit awhile to penetrate.. Expect they will break if not as they can get really encrusted.

 

[RandyT]

Remove the screen in the muffler and make sure it isn't plugged with carbon. If no screen then remove the muffler and check the exhaust ports on the side of the cylinder for blockage. if no blockage there then start the saw without the muffler attached. If it runs fine there then install a new muffler because it is clogged internally.

See the bolded corrections on my original post

 

[arrow]

See the bolded corrections on my original post

Yeah. Just detailing a bit for the op.

 

[yomax4]

Just curious but how messed up would your carb settings and fuel mix have to be to plug up a muffler?

 

[RandyT]

Just curious but how messed up would your carb settings and fuel mix have to be to plug up a muffler?

It isn't so much as plugging up the muffler the problem is the screen that is normally on the outside by the muffler outlet that you can remove and clean is internal to the muffler and if it plugs requires replacing the muffler because the screen is non serviceable.

 

[arrow]

It isn't so much as plugging up the muffler the problem is the screen that is normally on the outside by the muffler outlet that you can remove and clean is internal to the muffler and if it plugs requires replacing the muffler because the screen is non serviceable.

Not sure what you mean as "non serviceable". I've cleaned the screen a couple times by removing the muffler housing on the 50 series Husq's

To answer yomax. It is over time that these screens get plugged. On one of my Husq 50's, it took about 12 years but it happens. On mine, this saw would start, run and accelerate and after about a minute, it would simply shut down.

 

[RandyT]

Not sure what you mean as "non serviceable". I've cleaned the screen a couple times by removing the muffler housing on the 50 series Husq's

To answer yomax. It is over time that these screens get plugged. On one of my Husq 50's, it took about 12 years but it happens. On mine, this saw would start, run and accelerate and after about a minute, it would simply shut down.

Non serviceable meaning that the screen is not removable from the inside of the one piece muffler that is either crimped together or welded.Similar to a catalytic converter.

 

[yomax4]

Non serviceable meaning that the screen is not removable from the inside of the one piece muffler that is either crimped together or welded.Similar to a catalytic converter.

Yep, I forgot about the screens. Mine are all gutted and opened up but I can see the screens getting carbon'd up and causing a bad flow.