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

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On Sat, 21 Aug 2010 12:22:23 -0700, SF Man wrote:

I accidentally found I could test if the fuel line was clogged by pressing the accelerator pump bulb a few times with the two or three inch fuel hose out of the tank in the air with the filter attached.
The gas in the line went into the bulb until the line was dry as I continually pressed the bulb.
Then I dropped the attached fuel filter into the gas tank and continued to press the bulb a few times and it filled up with gas.
So, the fuel filter and fuel line aren't clogged. BTW, in hindsight, I knew this because the bulb filled with gas every time. If the fuel line were clogged, I would think the bulb would have been harder to fill with gas.
Anyway, it's not the fuel line in the tank. And, it's not the spark to the plug. So, I'm pretty much left with the fuel ratio at this point.
I guess it could be compression or timing.
Is there a test for two-stroke compression & timing?
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On Sat, 21 Aug 2010 12:28:19 -0700, SF Man wrote:

With the starter cord removed in the Craftsman 18 inch chain saw (358351800), I cleaned things out and noticed there are three separate fuel lines; but they all seem clear.
1. The thinner fuel line starts at the filter in the gas tank and goes to the bottom of the carbeurator.
2. It comes out the side of the carb with a thicker line and goes into the accelerator pump bulb.
3. Then it comes out of the accelerator pump bulb, again with a thicker line, and ends up near the choke plate.
There are two side-by-side plates; one is for the throttle; the other is for the choke. They appear to be working properly when I manipulate the controls. The choke plate has a hole drilled in it so you can't totally choke off the air.
So far, I can only find ONE screw with a spring on it which seems to be an adjusting screw. I will go back and look for the other.
BTW, I tested 'compression' with my thumb as I pulled on the starter cord before removing it and there was only a slight puff ... I wonder how to test compression and timing on a two stroke?
Do these things have points?
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On Sat, 21 Aug 2010 12:49:13 -0700, SF Man wrote:

The one adjusting screw seems to be at the level of the choke.
Surprisingly, I counted 8 full revolutions before it bottomed out.
I'm SURPRISED because I was expecting only one or two turns based on the adjustment procedure people said here (to back it out one turn).
Does 8 turns to bottom the adjusting screw for the choke plate seem odd to you? Should I still just back it out ONE turn?
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On Sat, 21 Aug 2010 12:53:22 -0700, SF Man wrote:

I looked all over. Maybe because it's a California chain saw, but I only see a single adjustment screw near the choke plate. Not two adjusting screws.
I screwed it out 1 1/2 turns.
Also I removed, as suggested, the baffle plate on the exhaust and the brass screen, both of which were sooty but otherwise wholly clear.
I'll see if that works.
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On Sat, 21 Aug 2010 13:05:49 -0700, SF Man wrote:

Oh oh. I read warnings about running two strokes too rich or at wide-open throttle. I run it at full throttle all the time (if I don't, it stalls). Is that bad?
Anyway, I figured I'd better google for Poulan carb adjustment procedures: http://www.gardenbanter.co.uk/lawns/1641-re-request-poulan-chainsaw-carb-tune-up-procedure.html
Will try that.
BTW, I learned in this video that the low and high have H and L stamped on them. Will look for that first.
http://www.youtube.com/watch?v=LhXGWF-B_hs

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SF Man wrote:

http://www.gardenbanter.co.uk/lawns/1641-re-request-poulan-chainsaw-carb-tune-up-procedure.html
timing is set by the flywheel key and usually not adjustable. They are usually pretty trouble free. What you can do is squirt some carb cleaner into the carb throat and that should get it to start for just a second maybe two. If it does and you know you are getting gas to the carb then you will have to clean the carburetor. The metering holes are very very small and it doesn't take much to clog them. One side of the carb is the fuel pump. The other side meters the gas to the engine. First I'd spray a little carb cleaner or a little gasoline into the carb and make sure the engine will start and run just a bit. Then the carburetor cleaning. Since it's only a year old the gaskets and diaphragms ought to still be good. The metering holes and jets are very small (emissions control) two strokes are considered dirty burning and the carburetors are made so you can't over richen the mixture which is what you really need at times. Anyway I've gotten small engines to run by priming them directly with gasoline or carb cleaner even WD 40 sprayed into the carburetor throat and if you can just get it to "pop" and run sometimes that will be enough to get things working enough to continue running. The screw that was backed out 8 turns probably doesn't matter since the carbs are now fixed with such metering holes. You will have to make sure those are clear when you have the carb apart spray carb cleaner into all the little holes and use compressed air to blow them out, there is a small screen also but those are usually not the problem. Old fuel is usually the problem it coats things with varnish and gum. You might get this thing running yet. Some of the youtube videos are very helpful.
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On Sat, 21 Aug 2010 15:57:48 -0500, FatterDumber& Happier Moe wrote:

This is an excellent treatise. It explains a lot, e.g., why I can't find the L and H carb screws (they're pinned apparently). And why the T screw didn't do anything useful.
BTW, I tried to "listen" for the snap of the spark across the gap but you just can't hear it because of the noise made while you're pulling the starter so that snap test will always fail. But, I can "see" the spark easily so I'm gonna assume it's the air:fuel ratio.
I guess it's time to take the carb apart. I have MAF cleaner in stock (xylene) but not carb cleaner, so, I'll have to stop off at the store about 15 miles away to go and get it.
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Timing, not sure about. Compression, tests like most other engines, I'd guess. Since it obviously spins easier with the plug out, you have at least some compression.
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On Sun, 22 Aug 2010 15:25:33 -0400, Stormin Mormon wrote:

That's a good point. It does spin easier (much easier) with the plug out. Also, I tried blowing abouit 50psi compressed air into the spark plug hole ... with mixed results.
- If the piston was at the top, it fluttered. - If the piston was at another spot, it blew out the exhaust. - If the piston was at yet another spot, it blew out the carbeurator.
But it never did run the thing (I think because of the pull-cord clutch mechanism because it 'looked' like it wanted to spin but couldn't spin. Probably because it wasn't fast enough to make the pull-cord clutch disengage.
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wrote:

Do you recall the color of the spark? A yellow/orange is a weak spark (bad plug gap or weak ignition).
A bright blue color with a loud "snap snap" is what to look for.
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On Sat, 21 Aug 2010 13:14:12 -0700, Oren wrote:

Bluish yellow. No snapping sound though.
Am watching this video to learn how to adjust the carb:
http://www.youtube.com/watch?v=LhXGWF-B_hs

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On Sat, 21 Aug 2010 13:18:07 -0700, SF Man wrote:

Doh. I just realized the "L", "H", and "T" embossed on the cover that I first removed indicated the low, high, and ... hmmm ... I guess "throttle" adjustment screws?
Both the "L" and the "H" pin are NOT screws. Clearly they are not designed to be adjusted. Again, this may be a California (smog) thing. To discourage you from touching them, there is a point instead of a screw slot; and they have a housing around them just so you can't easily get to them.
The "T" screw is easy to get to, even with all the covers on as there is a slot in the plastic to allow access. Do you think the "T" is for throttle?
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wrote:

If the T is for throttle - that may just fix your idle problem.
Is that the screw with the spring? When adjusting a screw, on the carb, count the number of turns it takes to seat the screw. Not tight, but just seated.
Back the screw out shy or past the number you wrote down.
Get it running and adjust a second time...
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wrote:

I would close the gap about the thickness of a match-book cover, trying to get a snappy blue spark.

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On Sat, 21 Aug 2010 13:14:12 -0700, Oren wrote:

It was a no go when I tried to start it just now. No catching at all.
If the spark is yellow mostly, how do I get it to be blue? I'll buy a new plug, but, how do I fix a weak ignition?
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wrote:

Try closing the gap a bit.
Oh, when you test a spark plug like this and ground it to the block - always make sure you have a shinny surface. Use good metal and not a painted surface.

Find us the online manual/link for the engine.
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The last time I held Sears to their gaurantee was on a Craftman electric weed eater. The design was such that after new line was let out via the bump line release (which worked pretty well), a blade on a plastic bracket was suppose to cut the line to proper length while it was spinning. The down side was, the design was such that it was a crap shot as to whether the new line would hit the bracket or the blade. If it hit the bracket, the bracket was flimsey enough to snap right off.
Sure enough, eventually the new line took out the braket and blade together and I returned the entire unit to Sears, whereupon the gave me a brand new trimmer, no questions asked. Sweet. Unfortunately, the design had not changed and after about and hour of hard use with the new trimmer, the line whacked off the entire bracket once again.
Perhaps their gaurantee no longer applies to "moving part" tools as you suggest, but it matters not. That was 30 yrs ago and the last Craftman tool I've ever bought other than an occasional screwdriver or nutdriver.
In all fairness, those "driver" hand tools are pretty good for the price. They also used to make awesome roll-away tool boxes. I once worked at a small start-up company that had a dozen mech-techs sharing the company's tools out of a couple Craftsman roll-away tool boxes. Those boxes were abused unmercifully, drawers being yanked open and slammed shut a thousand times per day. I was in awe of how well they held up and ending up buying a pair for myself. I still have it and it's an excellent product. I can't say if they are still as well made, today.
nb
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On Sat, 21 Aug 2010 14:41:54 GMT, notbob wrote:

They have a regular 1 year guarantee on the Craftsman chain saw.
The "hand tools" have the lifetime warranty, but the Craftsman lifetime warranty does not cover power tools. http://en.wikipedia.org/wiki/Craftsman_%28tools%29
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On 8/19/2010 2:57 PM, SF Man wrote:

I once showed a friend of mine a good way to check the ignition of a two cycle engine. I stuck an air hose into the empty spark plug hole and pressurized the cylinder then pulled the starter rope. The little motor ran happily on compressed air and the ignition system put out a nice big spark. It blew his mind (no pun). We set all of the needle valves in accordance with the manual, it indicated the number of turns the needle valves needed to be backed off from being fully seated. Of course, we cleaned everything first, making sure nothing was stopped up. After all our machinations, the little two cycle started on the first pull.
TDD
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I just realized that just before it stopped running, it ran really really fast. Of course, I had protective headgear on, but, even then, thinking back, it was running really fast.
I wonder ...
I wonder if I blew the rings somehow.
When I put my finger over the hole after removing the spark plug, and pulled the starter cord, there was only a small puff. Noticeable. But small.
Do you think compression might be the problem?
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