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testing a coil?

Started by teddy, October 17, 2009, 01:38:02 PM

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teddy

I have a husqvarna 142(I know a little saw!!!!!! But the misses likes it!!!!!!)

I have gone thru the whole thing! And can not get a spark!
How can I test the coil?

Thanks Matt (trying to fix the misses saw!)

sawguy21

Disconnect the wire to the switch to eliminate it as a possible culprit. With a spark tester (preferable) or a known good spark plug in firm contact with the cylinder, pull da rope. If spark, check the switch. If no spark, replace the coil. There is no point testing a coil, they work or they don't.
old age and treachery will always overcome youth and enthusiasm

Hilltop366

If when you disconnect the kill switch you don't get any spark the wire may still be shorted out on the saw you should pull the wire out and inspect it for missing insulation(wire rubbing or pinched on saw) , also do the same for the plug wire and check coil gap. The spark should be a blue snap, a yellow flash is not as good, check spark with a plug with no side electrode or bend the side electrode bent out straight.

I'm guessing you tried a knowed good plug.

sablatnic

Hilltop's plug without the side electrode is a good, cheap, easy test. And don't test it out in the sun. You might not see the spark. Don't ask how I know.

teddy

I have good spark!
gas!
Compression!

But just won't bite!!!!!!!!!!!!!!!!!!!!!

ERRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR

Al_Smith

Gas is good .Too much gas is bad .Were it a person would recomend a Beano tablet however it is not . In other words make sure the thing isn't flooded .

If you pull out a wet plug but know for  a fact the spark works trust me it's flooded .This goes right back to fuel delivety which goes right back to the carb .

teddy

Al's right!
The plug is WET!!!!
Going to try to adjust, before I rebuild the carb!
Thanks Al !!!! AGAIN

Hilltop366

Sometimes it's just flooded for other reasons like not pulling over fast enough, forget to shut off choke, cooled off enough to need choke but only for one pull and so on, you can "clean out" the engine by removing plug hold throttle wide open (no choke) and pull over quickly a 10 -12 times this will get rid of some of the excess fuel in the engine, reinstall a good plug and try to start, then go from there

teddy

I did clean out jug, installed new WORKING plug and it still is WET!
Still looking how to adjust the carb to restrict the gas!
Matt

joe_indi

Easiest coil tester is a digital tachometer.
with the spark plug out, hold the tach close to the ignition lead and pull the starter reasonably fast.If you get any rpm reading on the tach the coil is indeed putting out a spark.

But, the question is when?
Could be your flywheel  is twisted a bit causing a change in ignition timing, usually retarded.
While manually rotating the flywheel magnet towards the coil, keep a light contact with the piston top with a screwdriver, through the spark plug hole.
When the magnet is in line with the coil, the piston should be a wee bit away from reaching the top.
If the piston has reached the top or if it is moving downwards, the flywheel has lost its key and this needs to be corrected  with a new key.
If the flywheel is the type with a key molded into it and if its gone, boy oh boy, you will need to replace that flywheel. That is unless you have access to a machining shop which will put a groove into the flywheel and make you a suitable key.
Joe

bandmiller2

Joe,thanks so much for the two tips,their simple,practical and got to work.Frank C.
A man armed with common sense is packing a big piece

Al_Smith

 The odds are pretty great you just have a carb with the innards as stiff as a board .

Easy enough to figure out and simple enough to fix .Re kit the thing and be done with it . No sense try to massage a stiff diaphragm when the replacement kit is less than ten bucks and at best it takes a rank amatuer less than an hour to re kit it .I can do it in ten minutes but who is counting . 8)

teddy

The coil is good.
Just flooding!
I would assume the the carb. would only restrict the gas, not increase it to a flooding point?
Matt

Al_Smith

Well,you can fiddle with the carb , set the fuel lever low and crank in on the jets and likely get it to run but it won't run correctly .

If the innards of the carb are messed up there is no corrective action other than a rekit that will solve the problem .Many have tried but few have had success .

Now quit fooling around with it and get off that moldy money and order a carb kit and be done with it . :D --First though it might be a good idea to inspect the carb and see if it's assembled properly  and adjusted correctly . It wouldn't be the first time an incorrectley adjusted carb internally has caused much pulling of hair and obscenites to be uttered at random,whomever Random is .

teddy

I have pulled my last hair out!
Gotta be the carb!?!?!?!
I will order a re build kit monday!
Plus for only 2 years old! it needs a carb kit now!
I have an 066 that is well near 10-12years old and it is perfect!
Just odd to me that it would flood with a bad carb. assembly!
Something new every day

Matt

joe_indi

Now,
Is this a carb problem or something else?
To check whether  carb  flooding  is the culprit you could try this:

Empty  the fuel tank.
Remove the spark plug, clean it of fuel.
With the switch Off and throttle wide open pull on the starter about 8 times.
Refit the spark plug.
Move the switch to On.
With the control in fast idle pull the starter.
The engine should start, run for some time and then die out from fuel starvation.
If it still refuses start, you will need to look elsewhere, other than the carb, starting with the piston.

Just an after thought.
Did the current problem start abruptly or was it after something was done to it, like a cleanup job or something?
In that case, and if the saw has a primer, a strong possibility exists of the tubes from the primer being connected wrong.
The primer should be connected to draw fuel through the carb and release it back into the tank.
The primer does not draw fuel from the fuel tank directly  and pump it into the carb.

Joe

joe_indi

Quote from: joe_indi on October 18, 2009, 12:07:07 PM
:

Empty  the fuel tank.
Remove the spark plug, clean it of fuel.
With the switch Off and throttle wide open pull on the starter about 8 times.
Refit the spark plug.
Move the switch to On.
With the control in fast idle pull the starter.
The engine should start, run for some time and then die out from fuel starvation.



Do this without  the air filter

Joe

james

hold sparkplug wire with left hand , pull starter with right hand while holding metal body of saw down with left knee this will tell you if coil is good
(esp if pants are damp) ;D ;D ;D
james

joe_indi

Quote from: james on October 22, 2009, 06:49:32 AM
hold sparkplug wire with left hand , pull starter with right hand while holding metal body of saw down with left knee this will tell you if coil is good
(esp if pants are damp)
james

Do you need to comb your hair down after this test? smiley_big_grin3

Rocky_J

If your pants are not damp before the test, they probably will be afterward.  :o

Cut4fun

Teddy, if this is the 066 we talked about. Your psi is to low and all you are going to get is a wet plug.

sefh

Compression might be good but not enough. Put a compression tester on it and get back to us. 120 lbs or less your piston is shot. Should be around 150ish.
Stihl 056 27"
Stihl 290 20"
Stihl 026 20"

bandmiller2

Sometimes I'll test wico or FM magnetos with my thumb.With the cover off rest your thumb on the case about 1/2" away from the coil button and snap the impulse coupling you will know instantly if its good.The arc will jump to your thumb but not through your body no twitch just feels like a pin prick.Frank C.
A man armed with common sense is packing a big piece

Al_Smith

 Try that trick on a Wico roto master and let use know how well you make out . :D

They used those things on John Deere D's and I swear they could fire up on kerosine instead of gas . Talk about a hot mag ,wow .

This guy doesn't have a mag problem any way .

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