Bobcat Model 720 no spark

[sportster80]

Not sure why my other post went missing.

Hello,
I am really hoping someone can help me with this. I am working on this skid steer for a family member and I have ran into an issue that I cant figure out. I cant get spark to the plugs. I don't know the exact year but I believe it is early to mid 70's since it had points ignition. From what I can determine, the engine is a Wisconsin 4H4D or VG4D. It wouldn't spark from the beginning when I started.

Here is what I've done so far:
1. Changed the coil with a new one.
2. Installed a pertronix electronic ignition conversion in the points distributor.
3. Replaced the distributor with a pertronix 009b
4. Wired the coil and the distributor directly to the battery, just to bypass the wires from the switch to make sure it wasn't a wiring issue.
5. Tested the coil for power and ohms.
6. Tested the distributor with a multimeter by turning it over and checking for voltage spikes and drops.

I am at a loss as to why I cant get spark to the plugs. The wires look new to me and I have put in a spark tester to eliminate that its the plugs even though they look in very good shape. Does anyone have a clue as to what it could be?

 

[Wayne440]

You may get more useful answers if you will post the results of your #5 and #6 tests.

 

[SkidRoe]

Welcome to the Forum.

Oh boy, you have changed a lot of stuff!! Hard to know where to start.

I agree - what were the results from all of these tests? Have you confirmed that the distributor rotor is turning when you turn the motor over? May seem obvious, but you have not stated it.

Have you tried to contact Pertonix? They do have a technical help line.

 

[sportster80]

Not sure why my other post went missing.

Hello,
I am really hoping someone can help me with this. I am working on this skid steer for a family member and I have ran into an issue that I cant figure out. I cant get spark to the plugs. I don't know the exact year but I believe it is early to mid 70's since it had points ignition. From what I can determine, the engine is a Wisconsin 4H4D or VG4D. It wouldn't spark from the beginning when I started.

Here is what I've done so far:
1. Changed the coil with a new one.
2. Installed a pertronix electronic ignition conversion in the points distributor.
3. Replaced the distributor with a pertronix 009b
4. Wired the coil and the distributor directly to the battery, just to bypass the wires from the switch to make sure it wasn't a wiring issue.
5. Tested the coil for power and ohms.
6. Tested the distributor with a multimeter by turning it over and checking for voltage spikes and drops.

I am at a loss as to why I cant get spark to the plugs. The wires look new to me and I have put in a spark tester to eliminate that its the plugs even though they look in very good shape. Does anyone have a clue as to what it could be?

 

[sportster80]

Sorry all,

I have verified the rotor is turning. I guess I wasn't too clear that the distributor was on the engine when I tested it. I Just used the instructions I found online to test it with a multimeter and I was supposed to see spikes and drops in the voltage as the distributor turned and I'm getting that. The new coil Im supposed to be getting 3 ohms between the positive and negative and it tests good. Just to be safe, I have put a known good coil off my vw bug (which is also a 3ohm coil which pertronix says I need) on it and still get nothing. I am at a loss as to why I cant get spark.

 

[Wayne440]

The wires "look new"- but appearance is not a reliable indicator of electrical condition. Rob a known good wire and plug from something else and see if you get spark with the plug grounded to the engine. Make sure the coil is grounded as well.

 

[SkidRoe]

Good ground to the coil? Does Pertronix have a "test" function, where you can induce a spark? Have you called Pertronix??

 

[sportster80]

I have tried the distributor grounded to the coil and running both the coil and the distributor directly to the battery. There was a way to test the distributor by wiring it to the battery and spinning it checking for voltage spikes and drops, which I did and it to me tested okay. The issue is I could never get fire, with points in it, with an electronic ignition conversion in the distributor and now with a brand new one. Maybe I need some type of ballast resistor in the system that's missing. I guess I can call pertronix and see if they can help me, but the issue is that Im miles away from this thing so I can only work on it on saturday evenings and maybe sunday evenings. It was my brothers and he passed away and Im trying to help my sister in law. I feel like he was having the same issue as I found the boxes where he installed the new points, wires etc in his garage. Thats why I say the wires "look new".

 

[SkidRoe]

I am sorry to hear about your brother. From everything you have said, it sounds like you should have spark - this is not rocket surgery.

I re-read every thing you said - Can you verified that you have spark from the coil alone? Or at least check the resistance on the secondary winding? It should be in the k ohms scale.

I don't know what else to tell you.

 

[foton]

could it be that when the key switch is in the start position it is not giving the ignition 12 volts? so when you release the key to go in the run position then it is providing 12 volts but to late to start? I have heard of this.

 

[Wayne440]

...when the key switch is in the start position it is not giving the ignition 12 volts? so when you release the key to go in the run position then it is providing 12 volts but to late to start?...

I had a diesel generator with that issue. It had been improperly re-wired at some point and you could crank on it until the battery died- it would not hit one time. Just bump the starter enough to turn it twice and it would fire right up when you released the key.

 

[sportster80]

I wont be able to check anything until Saturday, but I wired the coil directly to the battery to bypass the switch. What is acts like to me is the engine itself is not grounded, but I don't see how that could be as its turning over with the starter? Does anyone know how to test the output of the coil while its wired? I have tested the primary and secondary windings using a multimeter and it off the vehicle but I don't know how to test the output while its wired up to a battery.

 

[SkidRoe]

Easiest way is to stick a spark plug wire in the coil, connect it to a plug and test it the way you would normally if the distributor were in circuit.

 

[sportster80]

The coil out goes into the distributor, wouldn't the coil never spark since its just always building current? Or it would fire as soon as there is enough built up to jump the plug?

 

[Wayne440]

The coil out goes into the distributor, wouldn't the coil never spark since its just always building current? Or it would fire as soon as there is enough built up to jump the plug?

The test described by SkidRoe will do the job.

The coil doesn't work quite the way you might think. Here is an explanation of common systems.

How Ignition Systems Work

Learn how the three types of ignition systems work – the conventional breaker-point ignition, electronic ignition and distributorless ignition.

www.championautoparts.com

 

[craigb93]

The test described by SkidRoe will do the job.

The coil doesn't work quite the way you might think. Here is an explanation of common systems.

How Ignition Systems Work

Learn how the three types of ignition systems work – the conventional breaker-point ignition, electronic ignition and distributorless ignition.

www.championautoparts.com

If you have a multimeter that has a tone continunity test position set it to that and connect across the points. One to points terminal and one to ground. Spin the engine over and you should hear the tone interrupted as the points break. A Pertronics module should act the same. If it doesn't replace with the points and try again. Set points gap @ 0.020-inch. If the meter only has a silent continuity setting you will have to be able to see the meter. Ignition/power not needed for the test.

 

[sportster80]

I have opened a ticket with pertronix support. I will post back if I ever find an answer.

 

[superjacob]

I had a diesel generator with that issue. It had been improperly re-wired at some point and you could crank on it until the battery died- it would not hit one time. Just bump the starter enough to turn it twice and it would fire right up when you released the key.

I had the same problem with my Yamaha generator (this model). I also reached their support and they helped me.

What did Petronix say about the problem?