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

[FatterDumber& Happier Moe]

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.

[Stormin Mormon]

It is hard for a zebra to change its spots (or some similar quote atributed to Al Gore.)

[Stormin Mormon]

Sounds like you spend all your time poulan on the start cord?

[Stormin Mormon]

Fuel filter is in the gas tank. There is a rubber tube, and the filter often has a weight, so that it stays on the bottom of the tank, as you tip the saw back and forth. You'll need a paper clip bent into a J-hook to pull the rubber hose and filter out.

[Bob Villa]

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.

[Stormin Mormon]

Same as lawn mower. Take the spark plug out, and hold it to a metal part of the body. Move to a dark area so you can see the spark easier. Switch to "RUN". Pull rip cord, look for spark at the plug gap.

[Stormin Mormon]

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.

[notbob]

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

[Red]

Hard to do on a chainsaw while holding the saw, the plug, the pull cord, and snatching all at the same time.

I made a short cord to do the trick. Has a standard alligator clip on one end and a battery cable clip on the other. The battery cable clip clamps to the spark plug body and the alligator clip to any convenient piece of metal on the motor. That frees up my hands for other things and keeps me from getting shocked.

[Jim Elbrecht]

They also make a spark plug tester that even allows you to adjust a gap to see if your spark is strong enough-- Unless you do it often, knowing whether you just have a spark-- or a 'strong spark' - is guesswork.

I'm sure a Google search for spark plug tester will turn up several tools-

Jim

[Scott Dorsey]

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

[SF Man]

Come to think of it, the chain saw DID start blurbling in a deep bass sound when I was tilting it while running.

It no longer runs. I will check out this hidden fuel filter and clean it out with compressed air if I can.

[SF Man]

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.

[SF Man]

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!

[SF Man]

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).

[SF Man]

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?

[SF Man]

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?

[SF Man]

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?

[hls]

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.

[SF Man]

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.