How do you start a saw that won't start?

[sawdust]

My desire to have more saws is increasing. This site is not helping. Now I am buying used saws. I don't know how to work on them, and I don't know gas engines. This week I got an ebay saw in the mail. I suspected I might have a problem when the saw came with the bar installed and the chain on backwards with a full fuel tank. Dumped green gas ( looks like real mix,I take this as a good sign). Put in fresh fuel. The saw won't start. I installed new air filter, fuel filter. The saw is clean and not dirty. Spark plug looks ok, but I don't know whats it supposed to look like. Pulled the starter cord to see if plug sparks, no spark. Then I realized, I don't know how to check for spark.Put new spark plug in plug wire, with proper gap, pulled handle and no sparks. Reinstalled plug in engine, pulled handle, saw started. Runs good. How do you check for spark? I have run 2 old Stihls I bought new around 1990. They always start and run strong so I never learned how to fix a saw or get one to start. Help! Cause I see more used saws showing up in the future.

 

[klickitatsacket]

1- pull the plug. 2- stick your pinky in the hole. 3- hold the threads of the plug between your forfinger and thumb. 4- make sure the switch is turned to the on position. 5- pull on the recoil rope really fast. If you jump and cuss it has spark. Or you can hold the plug to the cylinder to see if you have spark. I have a lighted spark tester that works really well. you can buy them at any auto parts store.

 

[sawdust]

Thanks Dean!

Thanks Klickitatsacket! Not turning the ignition on was my worst problem. What part of the plug do I hold to the cylinder?, the tip? Sounds like the lighted spark tester is the easiest. I'm on my way to turning into a gearhead! PS : How are my mufflers coming? Thanks again!

 

[2Coilinveins]

Sawdust-

Hold the threaded portion of the spark plug or the side electrode against the cylinder.

A lighted spark tester is great, but it won't tell you if the plug you're using is bad.

 

[chainsawworld]

1st-ignition. yes, a lighted spark tester is the best. some of these newer saws you can't groung the plug out on the jug. too much plastic in the way.
2nd-fuel delivery. if you have spark take an old pump type oil can a spray some mix gas into the carb. throat.
3rd-compression. gotta do it correctly with a gauge. less then 110psi she wont run.
if you lack spark, start out the easy way. look for cracked,thinnned or broken wires, bad switches and rust on the flywheel or if applicable, the points etc.
lack of fuel could be cracked or broken fuel lines or impulse lines, kinked lines. plugged fuel filter or carb. screen. streched metering diaphram. plugged impulse line.
no compression could be real bad or something as easy as stuck rings.
these are just possibilties and not limited to them. hard to fix anything over the net or phone. marty

 

[Gumneck]

Thought I would jump in with my woes here

I just put new rings/piston and crank seals into an older top handle metal craftsman. Also, has new fuel line/filter. 1)I did the rope handle check originally and the recoil would not hold the saw. 2)Saw originally tried to start when shooting mix into carb. 1 and 2 led me to the topend redo. Did a light honing to cylinder there wasn't any scoring.
My question. With my compression tester, how many pulls should give me the reading of the saw's compression? One only seems to get me to 70 lbs. By the second 90 third 120(of course without releasing valve on tester). I've used my tester on a mercury inline six before and other engines so I feel like I'm using it right.

I've got a new plug and has spark. My spark tester light flashes orange when pulling starter cord. Saw not going yet. Tks in advance.

 

[Gumneck]

Forgot to add

Forgot to add

Carb has been soaked and air hosed down. Rebuilt with new kit.


Anyone ....Anyone :Eye:

 

[Al Smith]

Get a little squeeze bottle,put some fuel mix in it,open the choke and throttle on the saw and give a little squirt of fuel,choke the saw and pull it over.If you get no response after several pulls,it's the ignition.If it fires and runs a short while,it's the carb.If it is the fuel delivery system[carb] check the height of the fuel shut off lever.If it is set too low,it won't open the fuel valve on impulse cycle,too high and it will flood.If the saw is modern enough to have a suspension system,check the impulse line for cracks etc.If rigid mount,check for the impulse hole[a small hole in the base]being clear.Check for cracked fuel line,and plugged fuel filter.With all that said,I'm out of ideas.

 

[runninghot]

Plugged muffler exit.

 

[Lawn Masters]

Plugged muffler exit.

Thats possible too. I use the fuel down the carb throat method on many saws that dont run.

 

[Ax-man]

.If rigid mount,check for the impulse hole[a small hole in the base]being clear.:

I have been wanting to ask this question for a long time, this impulse hole, is this a fancy way of saying " third induction port " I see this over at Mr. Acres site when checking out some of these older saws. Instead of a pulse line there is a hole in the intake manifold that mates to a hole in the carb to make the metering diaphram work. Someone had messed around with the 1-53 Mac I got and had the gasket upside down, so the "third induction port " didn't work. First thought was, it couldn't be this easy to get that saw to run, of course it wasn't, had other problems.

Larry

 

[Mange]

This is still common on saws, as is the problem with gaskets and carbon etc.

 

[Al Smith]

No,the impulse hole,is the impulse hole.I have a lot of McCullochs,but am not really an expert.A normal reed valve Mac has 6 intake ports,3 on each side of the block.Some models,of which I am not familiar with,had 9 ports.What the term 3rd port means,I haven't a clue .Maybe somone with more knowledge will step up to the plate and bring forth an answer to that.

 

[Gumneck]

Also forgot

Have added new fuel line all the way. New fuel filter. Exhaust port was fairly clean but cleaned to a shine anyway. Muffler clean. Is about .030 right for space between flywheel magnet and ignition armature? Spark seems ok from looking and grounding to cylinder. Its not a "wow" kind of spark but there is a spark. My tester flashes when I hook it up and pull. I've done the fuel mix down the carb with no response after putting back together. I'm thinking the module must be shot. I have cleaned the magnets with a light sanding as they were rusty.

 

[Al Smith]

About 12 to 15 thou on the coil.It could be possible for the insulator on the plug to be grounded or carboned up thus bypassing the gap.Not even a putt,geez.

 

[Gumneck]

I'll try the smaller gap. How about the compression question I had. Should I be getting 120 lbs+ on one pull or three? I assume leave throttle closed to check compression? Maybe not?

Tks,
tom

 

[Al Smith]

I don't have a clue,never took a comp test on a saw.Low comp or not,it should start.Besides that,new rings,not seated would most likely show lower readings.An example of such would be a McCulloch I rebuilt last winter.After the rebuild,I could pull the saw over without the use of the decomp.[7.5 cu in]Now,with less than 1 hr running time on the engine,I must use the decomp.

 

[Gumneck]

Stihl...NOT

Al
Tks for yr interest. I'm sure if this post had the word Stihl in it that all the gearheads would be posting replies. But it is just an old craftsman.

 

[Al Smith]

Most likely a Poulan in disguise.Besides all that,a saw is a saw.They all work the same way,some,however,better than others. Good luck.

 

[scottr]

Points ?

Tom , does this saw have points ?