Husqvarna 345 Shuts off when touch trigger

[PM Baker]

I have a Husqvarna 345, I always used non-ethanol fuel. Like 10 years ago, the throttle lock on top of the handle broke, so I removed it and duct taped the spring in the down position and used it like that every since. It has always started right up every time, even after no use in months. I pull the choke, push in the pressure release pin, pull the rope three times and the engine turns on and then quickly off. I push in the choke, crank it once or twice and it turns on perfect.

The last few times I used it, I started to notice that the saw will turn off if I let it idle for a minute or so, and it kept getting worse, it would turn off quicker. My solution was to just hold it in my hand and keep the trigger down a tad to make it idle faster to keep it from shutting off.

I noticed now that it will start every time if I pull the choke out then push it back in before I pull the starter rope and it will idle faster and the chain will turn, but as soon as I squeeze the trigger, the engine will shut off. I looked at the air filter and it is spotless, I looked down the barrel and it is spotless. I played with the L, T, H adjustment screws and it made no difference. As soon as I squeeze the trigger, it shuts off.

So, I looked at how the carb choke and throttle levers work ( see pictures) and noticed that when you pull the choke, not only does it close the choke butterfly but it also pushes the carb throttle lever a tad faster. When I push the choke back in, the choke butterfly opens, however, the choke lever that accelerates the throttle, does not disengage, it remains accelerating a tad the throttle lever on the carb. This I assume is normal operation and it is why the engine revs at a higher idle speed before and the chain turned, till I pushed the trigger. The trigger disengages the choke lever to the throttle, then the engine is at true idle, not fast idle. Now when I press the trigger, the engine goes to normal idle and immediately shuts off and unless you pull and push in the choke, therefore setting it in fast idle, the engine will not turn on.

How can I fix this problem?

 

[cuinrearview]

That is how the choke and fast idle work.

I've had three saws in that series that act very similar to that. The fuel line was rotten where it passed through the carb base on all three. If you don't see a milky white mess there, you may need a carb rebuild.

Is your cylinder OEM? I can't recall any of the 345s I've had having a decomp button.

 

[PM Baker]

Is your cylinder OEM? I can't recall any of the 345s I've had having a decomp button.

I bought it new in 8/2004 from Norwalk Power Equipment of Norwalk CA, the cylinder is OEM.

 

[cuinrearview]

Since it starts and revs up, spark probably isnt your issue. That leaves fuel and compression. If you have a tester, check that. If not, pull the muffler and post a pic of the ring and piston through the exhaust port. If that's good, fuel delivery is all that's left.

 

[PM Baker]

The ring and piston look spotless.

I fixed the problem by cleaning the carb:

I took off the carb, and just removed the two needles, L and H , and injected the two holes with Isopropyl Alcohol 92%, and then blew them dry with the compressor with the air separated from the hole so as not to exert too much pressure. That is all I did. I put the carb back on the adjusted the T, L, H needles and it runs great now. Thanks everybody for the help.