Service & Maintenance Question
Recently purchased 460 rancher. Ran great for two months. No...escalated
Service & Maintenance Question posted April 13, 2014 by matt enfinger
1465 Views, 4 Comments
Question:
Recently purchased 460 rancher. Ran great for two months. No complaints. Now it won't start. I've replaced the ignition coil thinking that was the problem but still nothing. Its like it just won't even try and attempt to start. The spark plug is sparking and it is getting gas. Saw is new can someone please help.
Answer
Matt,
A few questions, and then hopefully I will find an answer for you.
1. How is the engine compression ? Is it the same as when you bought it, when you pull on the cord without pressing the de-compression valve, does it have a good hard pull or does it pull easily? If you don't have the proper compression then the chainsaw will not start, even if you have a good spark, so check your compression. It is possible you have a stuck or partially stuck piston ring, one product which I personally like is "PB Blast (LMT) cleaner, its sold at most lawn mower shops or hardware stores, and also some big box stores, Its a (Lawn Mower Tuneup) spray. Remove your spark plug, and squirt a little into the cylinder, re-install the spark plug, let it sit for 30 minutes to an hour and then try starting the engine.
2. Is the decompression valve closing after one or two pulls or maybe its staying open? You can easily remove the de-compression valve with your chainsaw combination tool, and then while its in your hand push (opens the valve) or pull out (to close valve). There is a small hole in the side of the de-compression valve (about the gauge of 16 or 18 gauge wire) , If you push in on the de-compression valve and squirt a little WD 40 into the bottom, you should see a little oil drip out that side hole. The de-compression valve has to close to get engine compression.
3. Does your primer bulb fill almost full with fuel after pumping it a few times ? And does the primer bulb remain full even after pulling on the starter a couple of times ? It should also remain full even if you just let the chainsaw sit overnight. Its possible that your primer bulb is bad, there is a check valve inside the primer bulb which holds the fuel in the bulb, and keeps the fuel supply line full of fuel, however when the primer bulb check valve goes bad, it allows the bulb to drain back to the tank, and this will prevent the fuel pump inside the carburetor from pumping fuel, and from the engine starting.
4. If you remove the spark plug, after pulling on the starter for only two or three pulls, Is the Spark plug wet with fuel ? If it is wet after only a couple pulls then you have a carburetor problem, and your engine is flooding, there are a number of reasons an engine will flood, but that also will give you the same symptom, and the engine won't start.
OK, let me give you some time to digest the suggestions, I have made and Please get back to me, and we can go from here to solve the problem.
I hope this helps, I know its frustrating when an engine won't start properly, but don't give up. I will be glad to try and help you, also every engine that I have worked on has been able to start after one or two pulls.
PS. I am Not a Husqvarna Representative or an Authorized Repair, just an experimental chainsaw person.
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The compression feels good. The chain has a good hard pull. I've removed the spark plug and tried it in another saw of the same size and it worked fine. I've put a new spark plug in my saw and yet still nothing. I don't think its the spark plug. I originally thought it was the ignition coil and replaced it but turns out the old coil is fine so I put it back in. As far as I know, the decompression valve is closing. And yes, the bulb fills full gas and stays tight. And yes if I remove the spark plug it is wet with fuel. The engine isn't flooding.
Yesterday I had someone look at it and the only thing they cameup with was that the wire running from the off switch was burnt and he replaced it. I am just puzzled here. The saw is only 3 months old. I run ethanol free gas in it, mixed properly with oil. I keep it maintained and keep it inside out of the weather. Any suggestions someone please help. Stumped here.
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Matt,
Did you check or test the on/off switch, which should be easy to see next to the carburtor (red handle). The switch should be an open switch when in the on position, and when you turn the saw off the switch should close and ground the ignition coil.
I am not exactly sure how on a model 460 that it could be a switch problem unless the connector is not in the plastic switch (red handle) the correct way, and is always making contact with the grounding side.
If your Not sure If it may be touching, you can easily pull the connector out of the (red handle) with a pair of needle nose pliers, just remember how to put it back. Then put a piece of electrical tape over the connector, this will create a definite open switch. Then try starting the saw if it starts then its something with the switch or wires. Also remember if the saw starts, since you have the switch disabled, you will have to pull out on the choke switch to shut the engine off.
I may have a few other ideas but, Please verify that its not the switch or wires grounding the coil, and then get back to me and will go a little further. Or, If you already checked the switch and wires out, then get back to me.
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Matt,
I know you said that you had good compression, and I hope that 'm wrong but I like to eliminate the easy stuff before going for the more difficult stuff, but If you have checked the switch and wiring, then the next thing I would check is the piston and ring.
Its easy to check, and again I hope that I'm wrong but I have had engines that gave me the exact symptoms your stating.
So, remove the three bolts that hold the muffler on and remove the muffler, look into the exhaust port of the cylinder and inspect the piston, piston ring, and cylinder. Manually turn the engine over by hand slowly so that you can see the piston move up and down, you are looking for any scratching or scoring of the cylinder, piston or piston ring. Your also looking to see if the piston ring is moving or if it appears stuck in the groove.
The Cylinder, piston, and piston ring should be shiny with no grooves, nicks or scratches, again its an easy check but if you do have a score mark in the piston, and possibly through the ring, It may appear that the engine has good compression but I have had engines that will not start with a stuck piston ring.
Oh, while you have the muffler off, also check that the spark arrestor screen is clean, I assume that it will be clean with no carbon in it, but its another easy check, and I know you said this was a new 460 chainsaw, but these are things I check on every chainsaw when I'm troubleshooting.
I hope this helps, and again I hope I'm wrong.
I still have a few other options of things to check, so don't give up yet, just let me know what you find or don't find as the case may be.
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