Pertronix ignition acting strange hard to start

I

inairam

501 Club
Last winter I installed pertronix ignition and a pertronic coil on 1975 12 v Cub converted to an alternator. The battery and charging system are in great shape. The Cub has been working well all summer cutting grass with a belly mower and a tow behind mower. It also has been very easy to start. I do not think I used the choke all summer

This past week it has become hard to start cold and hot. It runs fine but hard to start. A friend of mine who once worked on old Ford electronic ignitions suggested pulling the spark wire out of the coil. The coil throws a very strong blue spark more than an inch out of the coil and then the tractor will start like it use to and run. If you push the wire back in it keeps running. If you turn it off it will have trouble starting. It will start fine if you pull the spark plug wire out

Other than the pertronix unit going bad any suggestions?
 
I have heard of problems with the petronix. I went with the much simpler and cheaper Velleman electronic ignition. It is basically a small circuit board that you build and it makes your points trigger the ignition through the circuit board and uses much less amperage through the points. Your engine runs much better and the points last way longer. You can also change back to stock really easily. I have not used this on my cub, but it worked great on my Mercedes 230SL. For around $20.00 this is a great deal. It claims it will work with 6 volt systems, not sure about positive ground though. If you have anything running points this is a really simple and cheap upgrade, and has been very reliable on my car.
 
Pertronics systems need at least 11.5 volts to operate on a 12 volt system . My suggestion is to do a voltage drop test on the battery while you attempt to start the engine.
 
plugs and wires were replaced when the pertronix installed.

battery and charging system also replaced at that time and all wire terminals and ground points cleaned with wire brush and or dremell but will do voltage drop.

But would not it be harder more demanding on the ignition system to start when the coil wire is pulled out?
 
When you pull the coil wire back, the spark is amplified allowing it to fire plugs that are somewhat fuel fouled. I know you said that your plugs aren't very old but pull them anyway and have a look at them. The fact that you say you haven't needed to use the choke tells me that it's probably running over rich.
 
the plug wires need to be the silicone type for electronic ignition also, not the copper style
 
All of the above suggestions.

Check ignition timing; low idle, in between, high idle. Check distributor to see that it's parts and functions work correctly, distributor hasn't slipped position.
 
no, you cannot use copper core wires with electronics, you need a resistor core type plug wire
 
tst":3dil3ua3 said:
no, you cannot use copper core wires with electronics, you need a resistor core type plug wire
Click to expand...

My '62 with 12 volt Pertronix died yesterday and will not start now. Cleaned the jet, plenty of gas flow. No spark! I noticed my plug wires are copper core. I know very little about electronics so what is happening with the copper core wires? Autolite 386 plugs.
 
I didn't change my plug wires when I went to electronic ignition. They remained as copper core wires. Starts right up and runs great on the pertronix. I also did not change my coil. Just stuck with the regular 12V coil with the resistor internal to the coil.
The Pertronix documentation does recommend a hotter coil and wider spark plug gaps.

Might want to review your timing settings. Maybe the pertronix magnet has changed position.
 
The only reason for the silicone resistor wired is for radio suppression. For the best spark use metal core wires with no resistance at all, unless you have a radio on your cub. If you use metal core wires and have a radio you would use 1000 ohm resistance spark plug caps. Anything more than that will rob spark power. The best is no resistance for the hottest spark. Also most modern spark plugs also have resistance built in. If the plug number has an "R " in it it is a resistor plug. The resistor plugs wont have as good of spark. So, if you don't have a radio you don't want any resistance at all in your plugs or wires.
 
I kept the copper plug wires on my Cub and 300 when I converted them to 12 and used the petronix. Using autolite 3116 in both and tapped at 0.032" with the 40000v coil.
 
To the best of my knowledge, the Pertronix does not care what type of plug wires are in use. The kit instructions do not mention it. I've installed them with carbon core, spiral core and metallic core wires and have seen no difference in performance or dependability. Coil selection is important! The ohm values listed in the instruction sheet must be followed. Stock coils generally work fine, as do the 40k Pertronix but beware of super high voltage performance coils, even the ones from pertronix.
 
I replaced my Pertronix today with a similar product from Hamilton Bob's after I could not get a spark from the coil. She fired right up! Not sure why the Pertronix quit working, it only has 8 easy hours on it. Maybe I left the ignition on too long without the engine running at some point.
 
first time i've had trouble with my petronix , the key was left on a "little while" by a novice driver on a recent halloween hayride ( it happens ) . intermittent spark . i replaced it with points and running fine . :surrender: coppersmythe..............................................
 
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