Help fixing old tractor

[OwnyTony]

I need help fixing an old tractor.  I dont know what year but its from the 70s i think.  It is a gas Ford motor made by Long (i think) and blue. 

I mistakenly put diesel in it (have another old Long tractor that is diesel) and now I cant get it to run again.  I siphoned out the diesel, ran some gas through until it pooled up in the carb (the part that fuel pools up and raised the float in the carb, sorry dont know the technical terms) and then drained the carb.  Did that about 5 times so I am pretty sure there is no diesel left in the tank, fuel lines and carb. 

I also changed out the spark plugs as i figure that they were foul from the diesel and also changed out the ignition coil. 
The problem seems to be that the new spark plugs are not getting a spark.  With my crappy multi meter, i can see that the voltage going into the ignition coil is at 12-13 volts (week battery) but i dont know how I can check to see if electricity is able to go from the ignition coil to the distributor cap and inturn, to the spark plugs.  I have taken the spark plugs out and “grounded” them to see if they were shooting sparks but nothing. 

I know I have discribed the situation in a very non-technical way but i hope you understad what I am trying to discribe. 

What would you guys suggest I do/where I should look.  The focus should be on the systems that affect the sparkplug.

[ryandalling]

Did you check the flux capacitor? I hear it needs 1.21 gigawatts.   

[Monsterlover]

if the distributor is feed by a spark plug like wire coming off the coil you can stick a spark plug right into that, ground the plug and see if it lights.

that will tell you if the problem is the distributor or farther upstream.

You're not missing a ground wire off something are you?

[Popeye the Sailor]

Panhead, Knucklehead? Sportster? Which one?

[Oldfisti]

Check your coil wiring and make sure it is hooked up same as before.  Don't hesitate to try the old one again.  If it has points make sure the contacts are clean and they are gapped properly. (usually .020 thou)  If the new coil has less internal resistance it is possible it burned the points and/or condenser.

[supertjeduc]

Spray some brakecleaner in the airfilter when you are starting

[ducpainter]

Check your coil wiring and make sure it is hooked up same as before.  Don't hesitate to try the old one again.  If it has points make sure the contacts are clean and they are gapped properly. (usually .020 thou)  If the new coil has less internal resistance it is possible it burned the points and/or condenser.

It has points....

good advice here

[OwnyTony]

if the distributor is feed by a spark plug like wire coming off the coil you can stick a spark plug right into that, ground the plug and see if it lights.

that will tell you if the problem is the distributor or farther upstream.

You're not missing a ground wire off something are you?

This sounds like a good idea.  If it sparks straight from the coil, then it should point to the distributor cap as the problem correct?  Also, If i were to try this, one thing i should note (which may be obvious to others) is the distributor cap has something on the inside that spins around to make contact to the other spark plug lines.  If you twist the cap, then it changes the "timing"?  of the engine.  
For example, the cap can twist both left and right.  Let say that I have it perfect so that when the engine is at TDC, the spark would ignite at that moment.  If it twist it to the left, it sparks slightly after tdc and right, it sparks before tdc.  
The reason why I mention this is because if I were to put a spark plug directly to the ignition coil, wouldn't it have one continuous spark?  Is there any problems with that or would it damage the coil or plug?

Fortunately for me, its on old engine so its more simple….analog/hardware swappable.  
Thanks for your help and suggestions.  I

EDIT: I only have time to work on it on the week ends so that is when I will try all of your suggestions (it is on a different property).  The coil was replaced before, last year i believe with a NAPA part and I replaced it with a new one(same part #).  Im sure the old one is still good but I bought an extra just in case and for diagnostic purpose.  Im sure it is wired like it was with the old one but I will double check that as well.  Also, I have stripped the carb down severl time to make sure its clean so im sure that is good.  In regards to brake cleaner when starting, i use starter fluid on cold starts or when it wont.  In thise case, i belive it is not getting a spark so no fireing up the engine.

[Monsterlover]

Yeah it would be a continuous spark. However, you're not going to light it for five minutes straight, just long enough to confirm spark

it either works or it doesn't.

[mitt]

I don't think it will be a continuous spark.  Once the coil collapses, it needs to recharge again before it can collapse again.  

The coil works by converting 12v to like 50,000v by the formula v=L*di/dt (voltage = coil inductance * change in current / change in time).  The change in current is big, and the change in time is very small.

If I have that wrong, let me know.

mitt

[Monsterlover]

I think mitt's right.

However I suspect the coil will collapse and recharge at a rate that's pretty fast and it would look much like a continuous spark.

It's been a long while since I've done this though.

Also a word of wisdom- if you need to stop an engine and you're by yourself and it's the type of situation that warrants not leaving the engine bay to go hit the key...

Do not grab the dist cap wire from the coil and pull it off the dist.

It hurts. And it keeps hurting until you manage to let go.

Instead, pull the wire off the coil and save yourself from the DIY version of "the chair"

[Speedbag]

Panhead, Knucklehead? Sportster? Which one?

[Howie]

I think mitt's right.

However I suspect the coil will collapse and recharge at a rate that's pretty fast and it would look much like a continuous spark.

It's been a long while since I've done this though.

Also a word of wisdom- if you need to stop an engine and you're by yourself and it's the type of situation that warrants not leaving the engine bay to go hit the key...

Do not grab the dist cap wire from the coil and pull it off the dist.

It hurts. And it keeps hurting until you manage to let go.

Instead, pull the wire off the coil and save yourself from the DIY version of "the chair"

On that old tractor, more like 18K volts if everything is in good shape.  Just holding the coil wire close to ground (with something insulated) while cranking wll work.   The spinning thingy is called a rotor (kids ). 

[ducpainter]

 

<snip>  The spinning thingy is called a rotor (kids ).