How do you "tune up" a hard-to-start Craftsman 18" chainsaw

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On Thu, 19 Aug 2010 19:50:07 -0400, Stormin Mormon wrote:

It would NEVER start with just 2x. The owners manual says to use 6x; the bulb has a 6x embossed just below it; and the complex starting instructions on the sticker on the side say 6x. Even when new, it barely started with 6x. It took more like 8x to 10x.
Dunno if it's a California thing or not but it just never ran well.
From what people say, I either need to mess with the screws on the carb or I need to find why (if) it doesn't have spark.
I can easily mess with the screws (after finding the procedure somewhere) ... but how do I tell if it doesn't have spark?
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As far as the run and idle screws...I start at 1 to 1.25 turns backed- out. The carbs on new stuff is pretty much crap these days.
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SF Man wrote:

No doubt a California discouragement system in it.
Never follow the instructions, find out what really works. Experiment. Something preventing it from running? Take it off and throw it away.
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On Thu, 19 Aug 2010 19:50:07 -0400, Stormin Mormon wrote:

Champion RCJ7Y. None of the stores carried that but they told me a Champion CJ7Y (without the R) is the same thing so that's what I put in there.
The plug, when pulled out hot, is dry as a bone so I'm pretty sure flooding isn't the culprit. I'm beginning to suspect either the plugged fuel filter (I didn't know chain saws HAD a fuel filter) or the spark coils are bad.
Don't know how to test the coils though.
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On Fri, 20 Aug 2010 20:02:04 -0700, SF Man wrote:

If the plug is hot, it's prbably firing. You can check this by pulling the plug, resting it against some metal and hold the saw steady while you yank the cord (have someone help, just keep them away from the blade!)
If it sparks, start looking for fuel not getting there.
Um, when I was in telephone support, they told us the FIRST question to ask was, Is it plugged in? I said, "you're kidding!" 30% of most problems were because it wasn't...
So, full tank? Fresh gas? And, is the fuel shut off closed?
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Hmm. If the spark plug comes out dry, that's a good clue.
You could put a couple drops of gas mix into the spark plug hole and see if it runs for a second or two. I've also sprayed ether on the air filter, that is a symptom check for fuel starvation. Only want to run it for an instant, as the saw relies on the oil mixed in with the gas to lube the crankcase bearings, rod bearings, and piston rings.
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The R means it has a series resistor for EMI suppression. Probably does not make much difference either way.

Turn the thing over with the plug removed from the engine, but sitting on top of the engine to make good electrical contact. If you see a nice hot spark, you have good magnetos. If you don't see a spark, your magneto or points have an issue.
Magnetos don't fail very often, but it happens. Fuel systems clog all the time, constantly. --scott
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Husqvarna, and some other chain saws, have had problems with the plastic gas line inside the gas tank cracking. When it does, the saw will be hard to start or not start at all. In many of these saws it is easy to replace the plastic tube with one of better quality, and replace the filter at the same time. A saw shop can do it for you, if yours is bad, or will sell you the improved fuel line.
You can check the ignition by pulling the start cord and observing the spark plug gap. Naturally you have removed the plug and have it touching the electrical ground of the chainsaw.
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On Sat, 21 Aug 2010 15:05:24 -0500, hls wrote:

Thanks for the tips.
This is apparently a Poulan motor in the Craftsman chain saw.
The three fuel lines appear clear and unbroken. Chain saw is only a year old. Fuel filter appears unclogged when I blow on it and has no visible deposits. It's bright white. When I press the bulb, gas flows (I can tell because I emptied it accidentally while I was holding it in my hands and it filled right up with gas).
Gas is new. Mix is new.
I'm working on the carb screw as I type ...
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It is not easy to see the crack in the line. Several models of chainsaws have had the problem, and it is not at all unusual from them to go bad within a year.
But the bottom line is to be sure you have fuel and spark, and if either is missing, you have to work backward to locate the problem. Remember the basics...you have to have spark (hot and at the right time), fuel, and compression to have the engine run.
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wrote:

Did you check the plug gap and set it? I'm not a fan of plugs that are pre-gapped. Male sure the plug has the proper heat range.

Follow the advise given here already about adjusting the carb jet/screws. I tend to adjust them while the engine is running -- tune by ear.
If the screws are bottomed-out, usually back it off to 1.25 - 1.5 turns out. That will get you in the ball park.
Pierce the gas cap vent hole with a paper clip so make sure the hole is open and vents the fuel tank.
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On Thu, 19 Aug 2010 17:34:04 -0700, Oren wrote:

Your problem may be no spark. Check the coils to see if they're putting out enough voltage.
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On Fri, 20 Aug 2010 23:36:49 +0000 (UTC), jm wrote:

What's the best way to check if there is spark?
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On Thu, 19 Aug 2010 17:34:04 -0700, Oren wrote:

The plug went in correctly. The only difference was I couldn't find the Champion RCJ7Y so I had to put in a CJ7Y.
Do you think it matters?
The store guys said it wouldn't.
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That's the day you should have returned it to Sears for exchange or your money back. Doesn't the Craftsman lifetime gaurantee apply to motorized tools? Now you know why I haven't bought a Sears Craftsman anything for 30 yrs!
nb
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On Fri, 20 Aug 2010 23:48:36 GMT, notbob wrote:

AFAIK, the "lifetime guarantee" only applies to tools sans moving parts (for the most part).
So, anything with a motor isn't covered.
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SF Man wrote:

You will have to ground the spark plug which isn't easy with all the plastic on today's chainsaws. I'm assuming you have a good spark though. I imagine what you will find is the typical set to run as lean as possible until it's out of warranty small engine. They do this to pass emissions tests. The carbs aren't adjustable as they come from the factory, some you can pull the plastic stops off the mixture screw and get a little more fuel to them some don't have the adjustment screws anymore. You can buy a new carb cheap on e-bay. cheaper than buying a kit and trying to fix one. With a little luck it will have both low and high speed mixture screws and you can get the chainsaw running better than new. And the fuel lines turn to gum especially with gasohol, and it goes on and on...... If you do get a replacement carb be sure to get the right one for your model engine Unless you like messing with small engines it might be best to find someone that works on them to get it usable. They should know all the tricks. Ask around and find someone that fixes small engines part time or for a hobby otherwise it won't be cost effective.
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On Sat, 21 Aug 2010 05:05:59 -0500, FatterDumber& Happier Moe wrote:

I thought the same thing. It's hard enough to START the thing, with one foot in the base of the handle, one hand on the top handle, and the other pulling the cord.
But, it turned out to be (accidentally) easy ... because I had removed the plug to test it. Putting the chain saw on the shop bench, turning the lights off, and pulling the cord was easy (sans compression).
It sparks like a champ. Thanks for teaching me that trick.
Next I'll try the fuel filter to see if it's 'clogged'. I do see a clear plastic hose, about a millimeter or two in diameter, that I'll try to fish out and clean with compressed air & report back.
Thanks for the hints!
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On Sat, 21 Aug 2010 12:10:45 -0700, SF Man wrote:

Using a paper clip, I fished out the clear plastic fuel line out of the fuel tank of the Craftsman chain saw.
On the end of the fuel line was a 1-inch long white cylindrical tube of the strangest material. Not hard like diatomaceous earth but not soft like felt. Dunno what it's made out of.
It does not seem dirty in the least nor does it appear to be 'clogged'. I blew on the end as the tip is smaller than the opening in my compressor air gun.
I could put the fuel line temporarily back in without the filter to prove it's not clogged but it really doesn't appear clogged in the least. I don't see ANY sediment whatsoever nor is there undue 'resistance' when I blow on it (there is some resistance but I assume that's from the filtering element).
I do see some "screws" near the carbeurator ... so I guess that's my next debugging step ... and to doublecheck if sawdust clogged some air hole somewhere (it's pretty clean as I blew it off with the compressor before taking the covers off).
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