Chainsaws

Bruce,

There are only five things you need to focus on to get a small engine too run, remember this Acroynym: "FACTS"

F = Fuel, you all ready stated you checked the fuel filter, and you are using New power 2 fuel, and I am assuming all the fuel lines look good, and no leaks, I would check the primer bulb, when you pump the primer bulb Is the bulb staying full of fuel or is it draining out? There is a small check valve inside the primer bulb that sometimes goes bad or the bulb develops a crack, if the bulb is not holding fuel replace it, be careful not to mix up the fuel lines during replacement, they are fairly reasonable priced too. If the saw is an older model 346xp and has been sitting over a season or two with fuel in the carburator, it is possible the carburator needs a good cleaning, and sometimes the fuel diaghram inside the carburator dries out and needs to be replaced as part of the cleaning, I would recommend an authorized Husqvarna Dealer do the carburator repair and adjustment if needed. But Please check out everything else, and come back to the carburator last.

A=Air, your engine needs a clean air filter so that it gets the proper mixture of fuel and air, If your engine is getting all fuel and no air, it will not fire, or if its getting just air and no fuel, it obviously won't fire, it has to have the correct mix. Also with air, carburators, and engines it is important that all carburator and engine gaskets are in good shape and that the engine is only pulling in air through the carburator, and not through a leaky gasket, this is a little more difficult to diagnose, but a service shop can pressure check the engine for leaks if you suspect a bad gasket. Also along with Air, is getting rid of the exhaust through the muffler, if the muffler or spark arrestor gets plugged with carbon the engine will be difficult to start, so check that your spark arrestor is clean in the muffler. The spark arrestor is an easy check, and easy to clean.

C=Compression, when you pull on the starter cord it is important that you feel a good amount of resistance which tells you the engine has compression, a worn piston ring will have some compression but may not be enough to start the engine. You can remove the Spark plug, and place a thumb or hand over the spark plug hole and feel the compression, in one direction when the piston is pushing up you will feel pressure, and as the piston moves down you should feel a good amount of vacuum. You could also check the compression with a compression gauge, but If your engine does Not have this Pressure/vacuum pulse the engine will not start, part of the reason is the carburators fuel diaphram operates off of this Pressure/ vaccum pulse, so the carburator won't pump the fuel without sufficient compression, also with the fuel going into the crankcase, the piston has to pull enough vacuum to pull the fuel/air mixture to the top side of the piston before it fires, or it won't fire. If its an older engine and your not even getting a puff or pop when starting it could be a worn piston ring.

T=Timing, this is typically not a problem on 2 stroke engines, this is controlled by the position of the flywheel, and the position of the ignition module, and unless you completely took your engine apart, or removed the flywheel, then this should be intact, However on 4 storke engines (ie, Lawnmower engines, it is possible for the flywheel key to get sheared and then the flywheel moves and changes the timing)

S=Spark, there are several spark testers on the market which enable you to test the spark plugs spark, when you pull on the starter cord and get a few revolutions of the flywheel, the ignition module should create High Voltage spark at the spark plug, if you are not getting spark its possible the ignition module is bad, or its also possible that the start/run switch has a problem. when the start run switch is placed in the stop position, it grounds out the ignition module and stops the spark, if your switch is not working properly it will appear as if its grounded all the time, and no spark. So If you know how to check for spark, change the position of the start/run switch and make sure you are getting spark.

I have used the acroynm "FACTS", many times and it always works, its actually a process of troubleshooting and elimination. The fuel system is usually a good place to start with troubleshooting.

I hope this helps, Please let me know what you find as a problem, I also may have some additional suggestions that you can try!