Husqvarna 145BT backpack blower problem

[spurlocktool]

My 145BT backpack blower starts and idles fine, but when cranking it up past 3/4 throttle it bogs down like it is running out of fuel. History: got it second hand from a private party but it was brand new, never fueled up. From day 1 it had this problem. I confirmed a lean condition by holding the throttle full on a few seconds till it bogged, then closing the choke part way - that made it rev up again but of course not run really right because of the restriction of the choke. After checking the obvious carb and fuel system parts, and this being the California smog model (CARB II) I assumed the factory had somehow just set it up too lean. So I drilled out the main jet a few thousandths and it would then rev up and run fine. Then after a few months the same symptom came back, so I enlarged the main jet a bit more and all was well. Now a few months later the symptom is back again. Obviously I am treating the symptom and not the problem by increasing main jet size. And actually the symptom is just a bit different now in that when run at full throttle, engine speed will rev to full rpm for several seconds, then bog down like it has just run out of fuel. Back off the throttle to half and it immediately starts running fine at the lower throttle setting. As long as I don't open the throttle past about half way it runs fine. Increasing to full throttle works fine for a 10-30 seconds, then it boggs and I have to reduce throttle.

I am thinking there is a problem with fuel delivery from tank to carb at high speed, but can't see anything wrong with the supply line, in-tank filter, or tank vent. I have also seen one other report of this same problem on another forum. Anyone have experience with this problem?

 

[stevess]

i've experienced the problem on newer engines. specifically my troy bilt weed trimmer 4 cycle engine. does the exact same thing as your describing. tried cleaning the carb, adjusting valves, checking the screen on the muffler. nothing seemed to help and i'm still trying to figure it out. while it was bogging i got so frustrated i strated grabbing the fuel lines and overflow lines pulling them in and out of the tank and for some strange reason it seemed to help. it's got to be in that area.

 

[collector121]

I have a similar problem with my 145bt. At first I thought it was the obvious stale gas and dirty carb but after an extensive cleaning, fresh gas and a new spark plug, I still have the same problem. It will start up and idle fine, but whenever any throttle is applied it bogs down like its not getting fuel. Im thinking either clogged fuel filter or coil. Any ideas? Thanks.

 

[spurlocktool]

I've heard of others with the same problem on this model, so it is apparently not uncommon. I suspected fuel delivery problems, but the fact that I can pump the primer bulb repeatedly and get plenty of gas flowing up the black fuel line and back down the clear one into the tank should mean the filter and line are OK. I really doubt it could be a coil problem, that should make it quit altogether or else misfire when run at full throttle. Also, the fact that on mine I can make it run so-so at high throttle by putting the choke most of the way on indicates a fuel or mixture problem. Since others seem to have this problem, maybe there is a service bulletin out on it. Maybe I'll try to ask a Husky repair center tech about that. Will let you know if I fine out anything.

 

[collector121]

ok thanks

 

[richamor]

It could be the fuel. It seems that Husqy specifies premium fuel for some of their equipment.

My Poulan blower does the same thing until warmed. I burned the piston in a new Husqvarna chainsaw using regular gas (at least that's what the tech said). It's new Echo replacement ran like crap until I switched to premium gas with Startron additive.

With the Startron I haven't had any problems....so far.

 

[spurlocktool]

Problem solved! It turns out to be a fuel delivery problem after all. The black fuel line had a split in it just inside the tank. The line runs from the filter up through a rubber grommet in the tank and to the carb. I pryed the grommet out of the tank, pinched off the line near the filter and blew through the other end and heard a leak. The line was split just below the grommet. I replaced the line and all is well. I discovered that by pulling on the old line it easily tears into pieces, no stronger than cooked macaroni. So it must be a bad batch of fule hose they used. Hope this helps others with the problem.