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krystolo

No spark, points question

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krystolo

I feel like I'm on a wild goose chase here.  Fun, at times, but whew!

 

I think I have the charging system sorted out, but still not turning over. I laid the spark plug (tested two brand new ones) on the engine, and did not see a spark.  Does this mean the condenser is bad?  Using the MM, it seems that power is getting to the condenser, but no spark.  Bad wire to the plug?

 

Are the points supposed to actually touch when the engine cranks?  I'm getting power to the point, but when I watch it move, the end of the screw does not make contact.  Is this right?

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stevasaurus

There is no screw that makes contact.  With the points mounted the 2 flat thingys move apart when the engine cranks and then they come back together.  When the cam separates the thingys, that is when you get the spark.  The gap should be .020 when the points are open to the fullest.  Obviously no spark when the points are closed.  If your points are set correctly, no spark could be condenser, plug wire, or bad points wire.  Does this make sense??  Take a picture of your points set up.

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krystolo

@stevasaurus I watched a video and understand better how it works.  Ran out of light, but will check in the morning.  I was thinking the screw where the wire attaches should touch the metal plate under it, but now I know where to look for the points.

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stevasaurus

Sorry, I am not real good at understanding some things that are said...I do better with pictures. :confusion-confused:  OK, the screw that holds the wire has the wire clip in between the tabs so it is not grounded to the points base.  Hope that helps.

 

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krystolo

Here’s the point breaker. 
 

I tightened the screw and added more dielectric grease. 
 

when I check with the MM, it reads 0 ohms both directions from the screw on the breaker to the negative post on the coil. It does not vary at all. I read it is supposed to go to zero, then build back up?

 

thoughts?
 

 

6BA22094-E932-48DA-AAA8-5A412088FF24.jpeg

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Mickwhitt

I don't use a multi meter, although the method is the same. I use an led lamp with Croc clips on the wires. The positive wire goes on battery positive terminal and the other one to the points wire terminal.

Turning the engine by hand using the flywheel, in the correct direction I.e clockwise when looking at the flywheel the lamp will be lit when the points are closed. As soon as the points start to open (breaking point of the electrical circuit, hence the name) the lamp will go off. This is when the spark plug should fire. This is when you check the timing marks on the flywheel. Do not move the flywheel at all and look through the sighting window on the engine tin at the front of the engine. There are two marks. T and S  the T is for top dead centre where the piston will be at the top of its stroke (if the flywheel is correctly fitted and the key is not sheered) S is for spark so at the instant the points break the S should be next to the timing marker on the cast aluminum bearing plate. Start with the points fully open and the gap set to 20 thousandths of an inch with feeler gauges as a base, then alter the gap by tiny amounts till the S mark lines up as the points break. I will post some photos of the process. Its the same as using a meter but no fussing with what it reads, the lamp is just on or off.

Hope this makes sense. 

Mick 

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ebinmaine

With the key on do you have 12Vpower to the positive pole of the coil?

 

 

After you verify by eye that the points are making contact, take a fairly decent dollar bill... Open the points and put the bil in there ... Pull it straight out. Slowly. Obviously you should feel some resistance. 

Repeat maybe 3 times. This cleans the points. You may have dust built up in there. 

 

Remove the plug wire completely and test for continuity. Be sure spark CAN travel that. Then check it for Ohm resistance with the multi meter. 

 

 

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953 nut

With the spark plug removed, ignition off, PTO lever forward and the transmission in neutral you should be able to turn the engine over by hand. Slowly turning the PTO bell in a counterclockwise direction observe the ignition points. The points will open once every two revolutions of the engine. When they open the maximum amount the open should be about 0.020" prior to starting to close. If they aren't doin this a small adjustment may be needed. Also, the wire should be pointed downward so it will pass through the opening in the points cover.

416207733_ignitionpoints.jpeg.d852e7473ee68a42d3d2be86b09767e0.jpeg

 

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Achto

:text-yeahthat:

 

After you set the gap on the points turn the engine over by hand until the points close. With the key in the off position open the points by hand and slide a piece of fine sand paper between them (600 grit or finer) let the pints close on the sand paper. Work the sand paper through the points a few times to clean them up. Then repeat this process using a dollar bill or a piece of paper instead of sand paper. This will clean the contact surface of the points. When finished remove the wire that goes to the coil. Check with your multi-meter from the terminal that you removed the wire from to the body of the points or ground, you should have continuity when the points are closed and no continuity with them open. If you don't have continuity when the points are closed then clean the contact surfaces again.

Edited by Achto

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krystolo
5 hours ago, ebinmaine said:

With the key on do you have 12Vpower to the positive pole of the coil?

 

 

After you verify by eye that the points are making contact, take a fairly decent dollar bill... Open the points and put the bil in there ... Pull it straight out. Slowly. Obviously you should feel some resistance. 

Repeat maybe 3 times. This cleans the points. You may have dust built up in there. 

 

Remove the plug wire completely and test for continuity. Be sure spark CAN travel that. Then check it for Ohm resistance with the multi meter. 

 

 

So, I have voltage to the negative pole of the coil, but not the positive pole. How can that be? 
and the coil gets really hot when I leave the key on run. 

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Achto
21 minutes ago, krystolo said:

So, I have voltage to the negative pole of the coil, but not the positive pole. How can that be? 
and the coil gets really hot when I leave the key on run. 

 

Disconnect all of the wires from the coil. Find the wire that has power when the key is on. This wire will go to the "+" side of the coil. The wire from the points and the wire from the condensor will go on the "-" terminal on the coil.

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Achto
54 minutes ago, krystolo said:

coil gets really hot when I leave the key on run.

 

If the key is in the run position and the points are closed this will cause the coil to heat up and can damage the coil. It may also burn the points contacts. If you need to have the key in the run position for an extended time while trouble shooting then I would suggest removing the wire from the "+" side of the coil and isolate it.

 

Short tests (30 sec or less) with the key on and the engine not running will not cause damage to the ignition system.

Edited by Achto
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krystolo

Update:

rechecked everything, I was mistaken earlier. 
I have power from battery to ignition switch, through solenoid, and to positive pole of coil. I have power through spark plug wire to the cap thingy on the plug. 
 

I do not have any voltage to the negative pole of the coil or the points. When switch turned to run. 
 

Maybe I damaged my coil by leaving it on run?

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ebinmaine
7 minutes ago, krystolo said:

I have power through spark plug wire to the cap thingy on the plug

 

 

All the time?

That should flash when the engine is turning over...

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squonk

Ok I'm going to try to help. (too many cooks spoil the sauce) :) If you don't have a 12volt test light get one. You can leave your meter in the toilet on this one. You can get a light at any parts store. Looks like an ice pick with a lead and alligator clip on the end. clip the alligator thingy to a good ground. Turn the key on. Touch the pointy thingy of the light to the + terminal of the coil. The light should light up. If it does not you are not getting 12 volts to the coil. If it lights up, now touch the pointy thingy to the negative and turn the key to start. With the engine turning, the test light should flash on and off. If it doesn't come on at all, the primary circuit in the coil is most likely fried. You need an internally resisted coil. Napa # IC14 or equivalent. The other possibility is the points are not closing and making contact. If it lights and does not flash, The points are not opening and breaking the circuit or the wire going from the - terminal of the coil to the points is grounded.

 

The coil has 2 circuits. The primary is connected to the plus and minus terminals of the coil. When the points are closed the circuit is completed and you have primary current in the coil. This builds up a magnetic field in the coil. When the points open, the circuit opens and the magnetic field collapses. The field collapsing INDUCES A HIGH VOLTAGE into the secondary winding in the coil. This is connected to the center post of you coil. The secondary circuit is completed through your plug wire then to the spark plug where it jumps the gap to ground.

YOU CAN HAVE A MILLION VOLTS ONTHE PRIMARY CIRCUIT! BUT YOU WONT GET THE PLUG TO SPARK UNLESS YOU COLLAPSE THAT CIRCUIT TO INDUCE THE VOLTAGE INTO THE SECONDARY.

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krystolo

Sigh...

 

The coil checks out, light flashes on negative terminal. 

 

I can see the points open and close and see a spark. Points gap 0.020. 

The voltage fluctuates in the spark plug wire cap when I turn to start.

 

Spark plug gap 0.035

 

I tested compression with my thumb and it blew it off. (No thumbs harmed in the making of this tractor fix 😜
 

just not turning over

 

how long is it safe to keep cranking?

 

thoughts?
 

Edited by krystolo
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squonk

First Krystolo. If the engine is cranking, it is turning over. Saying it's not turning over can confuse someone trying to help. Do you have a spark tester? Napa has a cheap one that works good.

 

Spark Tester, Inline BK 7760017  #776-0017 $10.00  This will test to make sure you have enough voltage to jump the plug gap. If you have spark then it sounds like a fuel problem. You had the carb apart. The bowl was emptied. Perhaps the fuel pump is weak and not filling the carb bowl. Another possibility is the fuel filter in the shut off vale is clogged at the tank.

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ebinmaine

To clarify:

 

When you turn the key to start...

The engine does spin but does not start and run on its own?

 

Do you have any carb clean or brake clean?

Or a small amount of gas you can squirt into the carb throat?

 

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lynnmor

:text-yeahthat:

Test by putting a small amount of fuel in the carburetor throat, then immediately crank.  It the engine fires a bit then you have a fuel delivery problem.  Squirting random solvents may not prove anything as some are not flammable.

 

A quick and dirty tester for spark is an old spark plug gapped nearly twice as wide as specification.  Any old plug will do.  Connect the spark plug wire to it and lay the threaded portion against the block, then watch as you crank.

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ebinmaine

@krystolo

Just as an FYI...

When I empty the fuel system of my own C160 it WILL NOT pull fuel all the way from the tank. 

 

I have switched over to using a blue see through fuel line on all our small equipment so I can see if there's fuel flowing. 

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krystolo
2 hours ago, squonk said:

First Krystolo. If the engine is cranking, it is turning over. Saying it's not turning over can confuse someone trying to help. Do you have a spark tester? Napa has a cheap one that works good.

 

Spark Tester, Inline BK 7760017  #776-0017 $10.00  This will test to make sure you have enough voltage to jump the plug gap. If you have spark then it sounds like a fuel problem. You had the carb apart. The bowl was emptied. Perhaps the fuel pump is weak and not filling the carb bowl. Another possibility is the fuel filter in the shut off vale is clogged at the tank.


whoops! Sorry about the terminology. 
 

I’m pretty sure there is fuel in the bowl because the bolt at the bottom was actually a little loose and gas was leaking out, but I will double check and try the carb cleaner trick @ebinmaine suggested. 
 

will also get the tester.  

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krystolo
1 hour ago, ebinmaine said:

To clarify:

 

When you turn the key to start...

The engine does spin but does not start and run on its own?

 

That’s correct. The wheel spins, breaker opens and closes and sparks, but it never “catches” and runs. Rarr rarr rarr rarr

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ebinmaine
8 hours ago, krystolo said:

breaker opens and closes and sparks

 

I've not messed with points much so I'll defer this question to others....

 

Should the points spark?? I kind of thought not. 

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953 nut
13 hours ago, krystolo said:

Sigh...

 

The coil checks out, light flashes on negative terminal.    This is good!

 

I can see the points open and close and see a spark. Points gap 0.020.   A small spark as the points open is normal, your condenser will quench the majority of the spark but not all.

The voltage fluctuates in the spark plug wire cap when I turn to start.    With the spark plug connected to the plug wire and laying on the cylinder head is there a spark that will jump toe >035" gap?

 

Spark plug gap 0.035            :handgestures-thumbup:

 

I tested compression with my thumb and it blew it off. (No thumbs harmed in the making of this tractor fix 😜)     :handgestures-thumbup:
 

just not turning over   After attempting to start the engine is the tip of the spark plug wet with fuel?

 

how long is it safe to keep cranking?      I wouldn't use your starter longer than ten seconds without giving it a rest, it has no cooling of any kind.

 

thoughts?        Did this problem exist before the carburetor rebuild?     
 

 

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squonk

Eric, You are breaking a circuit. It is not a crisp sharp break so yes they will spark. The little spark is what causes your points contacts to wear. If the condenser is bad, it will wear out the contacts quicker. (Bigger spark)

 

Also laying a plug on a head and checking for spark really doesn't work well all the time. Corroded aluminum head fins are a poor ground. Get a spark tester.

Edited by squonk
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