1951 VAC - no fire

[wod288]

Guys,

I am in a time crunch to make my local fair and show. I need some quick help! I"m desperate at this point. Here is my problem...tractor won"t start, I have replaced ground wire to 0 size, starter wire to 0 size, condenser, points, and coil. still no fire to the plugs... when we put test light on the points, we have power at the points..when we turn it over...power goes out..is there anyone out there that can help...I can call if necessary, just provide a number.

 

[Jerry W]

When you have your test wire on the points it should go on and off as the distributor rotates and opens and closes the points. When the points are closed it should be off because the ground in the distributor should be a better conductor than your test light therefore no light. When the points open the distributor circuit is broken and the light should come on.

In order to spark the coil the primary circuit (battery voltage) has to charge and uncharge. The high voltage in the secondary coil is released when the primary field collapses as the points close.

Jerry

 

[wod288]

Thanks Jerry. That makes sense. It does show just like you described. I noticed some arcing behind the dash near the amp meter. I readjusted those wires and it started. When it started it surprised me and I shut it off thinking we had it. Then no spark and no start. Later at one point it started again (had spark). I let it run a few minutes and then shut it off. Now, back to square one, no spark and no start. I"m still puzzled.

 

[wod288]

Now that I have been thinking on this some I realize I have to start the process of elimination, Any thoughts on the procedure?

 

[Jerry W]

I would run a hot wire from the hot side of the battery right to the input terminal of the coil and see if the problem is maybe in the switch or switch wires. I do not know if you or someone has changed it but stock would be (+) ground so then I would run a wire from the negative (-) side of the battery to the negative (-) side of the coil.

jerry

 

[wod288]

Thanks Jerry...I have to be simple about this so bare with me (my case is still original + ground). What you are saying is run a hot wire (18 gauge or so)from the negative battery terminal to the negative side of the coil to bypass the switches and gauges. Then hit the starter button and see if it fires. Right?

Thanks in advance.

Warren

 

[Jerry W]

Yes - Just be sure that your coil is wired right. With + ground battery the + terminal on the coil should go to the distributor.

Jerry

 

[RJKeith]

On my 300 when I first got it you would have to let it spin, then when you let of the starter the tractor would start. It got worse and worse to the point where it would not start at all, so I rewired it, including a new ignition switch. Same thing, so I buzzed it out and finally accepted the fact that my new ignition switch was bad as well as the old one. So I put a third ignition switch in and it starts great now, So check your switch and even the wires. And measure the voltage too! Don't just check with a test light.

 

[wod288]

Hey Jerry...Yes it does, we are good. I will try tomorrow and reply with my results.

Thanks,
Warren

 

[wod288]

ok Jerry. I have narrowed it down. with the test light on the (-) side of the coil, the juice is cutoff when the starter button is pushed. I then tested your suggestion and the tractor started. Now, I have to see why the starter button engagement is cutting the power.

 

[Jerry W]

If you have the stock 6 volt system it is probably drawing down because your starter is using it. Make sure your cables are big enough and have good connections all the way and that you have a fully charged battery in good condition.

This is why they went to 12 volt systems and solenoid start. Then they could still run the ignition at 6 to 8 volts by using a resistor but during start up they could bypass the resister to give the ignition a bigger shot of voltage.

Jerry

 

[wod288]

Hello Jerry, One thing to mention here. At the beginning of this process, I added brand new cables. I ran a new 0 wire from the (+) terminal on the battery to the top bolt that holds the starter on the frame (I disconnected the old one that was connected to a bolt in the battery box area). I did this to improve the ground and increase the efficiency of the starter during starting (it turned over real slow - it turns over much faster now). I also replaced the starter hot wire with a new 0 wire.
Reading all this, do you see anything incorrect?

Warren

 

[wod288]

thanks, it's going in that direction. I will reply when I find the problem.

 

[Jerry W]

If your points lose spark when you crank it and the cables are all good then it about has to be the starter. It would be interesting to see how many amps your starter is drawing. I don't know what else it could be.

Is the coil OEM or equivalent? Some aftermarket coils are internally resistored and that is NOT what you want.

Jerry

 

[wod288]

Thanks Jerry. Even the old coil will work so I doubt if that is it. I got the coil from Tractor Supply so I have to see if it is OEM specs.

As for the starter, I had not thought of that. I will see if I can check the amp draw.

Thanks,
Warren

 

[wod288]

Well, I was messing with the tractor again today hoping to get it to the fair where more guys could help me but, even with the jumper wire it would not start. When the starter button is pushed, the power goes out to the coil. Even with the jumper wire. Do you think it would help to jump the starter with 12 volt battery and see if it cuts the juice at that time? Also, how to check amp draw at the starter?

 

[Jerry W]

I just got to believe that the spark goes away because either your battery doe not have the capacity or your starter is drawing everything your battery can put out.

 

[Jerry W]

It should not hurt to jump it with 12v or a boost with a charger. I just make sure that when I remove the cables that I remove the ground first and not near the battery because a charging battery gives off very flammable gas. Prefer a ground hooked up to the chassis instead of a battery post.

 

[wod288]

You may very well be right on the starter drawing too much. Here is what I am thinking of trying: Disconnect the power wire to the starter from the tractor. Jump the starter with a separate 12v battery using jumper cables. Hot wire to starter terminal and ground to the starter casing. I think it will start that way. I'm not good with electricals, will this be ok?

 

[Jerry W]

That should work ok.

WOD288 You are on your own now. I am leaving to go on vacation for a few days. Hope you find the problem.

Jerry