Why do ignition points need so much attention these days?

[slowleak]

I've been around small engines all my life, back in the 70's when everything still had ignition points, we rarely had to mess with them. It seemed like they were a set 'em and forget 'em thing.

Now, if I put new a new set of points, & a condenser in a mower, a week or two later they need to be cleaned again.

I picked up an older Rickles Home Centers push mower, the thing looks like brand new but it had no spark. I pulled the flywheel, and took a close look at the points and they looked fine but with a bit of corrosion on the surface. I dragged a bit of emery paper throught them and it regained spark. With some fresh gas it ran fine. That was Sat.
Now, several days later, it again has no spark.
I tear it apart again, replace the points with a fresh set from B&S gapped at .020", resealed the little points cover, and put it all back together and it fired right up. This morning, its got no spark again, the points again failed to make contact.

I gave up and stuck a Nova module on it.

But, what changed? The points are older inventory, so not from China. the condenser tests fine even on the original set. They weren't burnt or pitted, just dirty or lightly corroded. They only sat over night, it was running when it shut down, then 12 hours later no spark.

I've had this happen over and over again lately.
There is no oil leaking into the points cover and all it takes is to wipe a bit of rough cloth through the points to restore function. I've been dealing with this on both push mowers and tractors. I've even intentionally left the flywheel off, and tested the point for continuity and they were fine when it got turned off, but after few day sit, they loose continuity. These are all machines that are stored indoors in a shed or garage. The very same building I've been keeping my mowers in for 40 years.

 

[Auto Doc's]

Hello S.,

First rule of points is to not touch the contact surfaces. The oils from a person's skin will contaminate and etch the surfaces. Briggs and Stratton even had a huge issue with this back in the late 70's, and they tracked it back to the assembly line folks who were packaging the tune-up kits.

I always drag a small piece of white paper between the closed contacts a couple of times to make sure there is no residue left behind. That has worked well for me.

Contact points are also really moody when there is high humidity.

 

[slomo]

I dragged a bit of emery paper throught them and it regained spark.

Too aggressive of abrasive choice.

Contacts need polishing. They make contact cleaning paper or used to.

If the contacts are pitted you have one caveman try with low grit paper. Then polish to a mirror shine. Use some Flitz Metal Polish or the like and a slim cloth. Even a sheet of thick copy paper.

Once polished the points need tested with an Ohm meter. Need to see near to 0 Ohms or a dead short as possible. So hitting them with 100 grit and expecting them to last for decades is reaching a bit.

Most of the time the condenser provided doesn't work or is a pirated copy of. Bad condensers can cause pitting.

 

[Auto Doc's]

There are rare occasions I still deal with points in antique vehicles and equipment, so I have a points file in each of my toolboxes. I get some funny looks when I pull that small file out because many folks do not understand what I am doing.

Many folks these days prefer an electronic ignition conversion over points because they are low maintenance.

 

[slowleak]

I put brand new points and condenser in two of my mowers two weeks ago, both were new in the box B&S parts, new plunger, a new top engine seal on the one, and cleaned with a bit of cotton shirt soaked in Electomotive cleaner. The engine ran fine, started right it, bright blue spark. The next morning the points refused to make contact.

I've got my father's old 1965 Cornell branded 3hp B&S push mower he bought at Pep Boys that likely has its original points, its never once lost spark. I reset the gap once about 15 years ago. Yet the 1977 and 1979 mower, and two Gilson rototillers with 5 and 8hp motors both need the points cleaned nearly every time I go to start them.

They points aren't wet, they aren't oily, but they get a haze on the surface that prevents them form making contact. Sometimes if I pull the thing over long enough they begin to work if its not been too long.

I've been working on small engines and outboards my whole life, I find the same thing with outboards lately, if you leave the original points and just change the coils and condensers, they're fine. If you change the points, you get the same thing, they fail after a short sitting period.

On these B&S motors its the point contact themselves. What ever forms on the surface is non conductive and often invisible to the eye. Something makes me think they changed the material the points are made from over the years. Back in the day points were just never an issue, when wore down, you grabbed a set at the parts store an all was good. I used to get Arnold brand parts through a nearby auto parts store, those worked just fine too. But the last of those got used 20 years ago now.

I have also converted a few over to the newer coil but found that some motors won't fire the newer coil. My 1977 Rickles push mower with a 3.5hp BS motor is one of them. Being vertical pull model, I've never found a suitable flywheel to change it over. (I've got a few of that style motor that refuses to fire a coil, as if the flywheel magnets are wrong or bad, but they feel strong magnetic wise. That mower has been sitting on the shelf since about 1980 dead from no spark. I've given it new points, a new coil, nothing, then I took a known good Magnatron coil and mounted that up, and still no spark, with no kill wire connected. Yet the coil on it works on the other engines. Something is up with the flywheel.

I also have found quite a few of that style flywheel with cracks radiating out from the center hole underneath. I've got about 15 parts motors and about 5 of them are vertical pull start models from the 70's and not a one had a good flywheel. They are either cracked or won't fire a coil.
I've never had one fail that had the older Easy Spin Ratchet on top, or have I had a bad Quantum flywheel.

 

[Auto Doc's]

Being that most components are made cheaply and overseas, I suspect a low-grade tungsten carbide is being used for the points contact face. Along with that humidity is hazing them over due to the poor material.

 

[slowleak]

There are rare occasions I still deal with points in antique vehicles and equipment, so I have a points file in each of my toolboxes. I get some funny looks when I pull that small file out because many folks do not understand what I am doing.

Many folks these days prefer an electronic ignition conversion over points because they are low maintenance.

Not all flywheels work well with the electronic conversions. I'm finding that some mid to late 70's BS flywheels won't trigger the Magnetron coils or conversion kit. (I've never had one not work on an Easy Spin style motor though). I've got several '76-'79 vertical pull, gear tooth type flywheels that won't fire the newer coil, a few won't fire any coil despite having strong magnets. I've never been able to figure out what ails them.

I picked one up this morning, a 1974 model with that style flywheel with no spark. I cleaned the points, tested them with a continuity tester and they work, but the flywheel won't trigger a coil taken from a running motor.

As far as I know all of that style had points not the newer Magnatron coil.
They also refuse to work with the Nova module as well. I've used the Nova modules on motors as far back as the late 50's though.

I do find an big increase in torque with those modules for some reason but they get a bit harder to start, requiring more flywheel speed to fire. Where as a stock points motor will start with a light pull, once the Nova module or similar is on it you need to really give it a hard pull to get it to fire.
I have a Sears Rotohoe with a 3hp vertical shaft Briggs motor, it worked great with the stock points but was easy to stall, roots or any hard stop would kill the motor sometime shear the keyway.
When I added one of those modules it became a whole different machine. Its harder to start in that you have to really spin it to get it going, but when its running, its nearly impossible to stall. My guess is the timing is somehow changed just a bit for the better with those single wire modules.

I did a few checks on two identical machines and found that with the points the motor will rev to 3,650 or so and it will idle down only to about 1150 rpm, but with the Nova module, they max out around 3,400 but will idle down so low they sound like a hit and miss motor.
It must delay the spark a bit which give the thing considerably more torque.

I've used the Nova kits, a few BS conversion kits that go on the coil, and a few Kawasaki style one wire modules. They all work, but only the remote module seems to delay the spark a bit. I also find that the conversion kit is a hit or miss option only viable on the Easy Spin, ratchet recoil style models.

 

[slowleak]

Being that most components are made cheaply and overseas, I suspect a low-grade tungsten carbide is being used for the points contact face. Along with that humidity is hazing them over due to the poor material.

The only points I've been using are OEM BS points. I had some Arnold brand points and those were never an issue, likely just repackaged OEM parts, Most of those I have are older than 15 years old on the shelf. I bought all the BS small parts when one local shop closed, I was mainly after the larger hp points sets for the iron motors but made the deal for everything which worked out far cheaper in the end. I think I gave about $150 for the contents including the shelves and it filled my full size van. Selling off the Tecumseh parts online more than paid for the whole deal.

 

[Auto Doc's]

Hello S.,

I recently had a storm responder 5500-watt generator that was giving me fits due to weak ignition fire. I replaced the coil with a used one and then a new one, but the problem was still there. Yes, the coil mounting towers were cleaned to new metal.

To cut to the chase, the coil mounting screws were the problem that I found. The screws were the last possible thing that I would have thought of, but all other possibilities were eliminated. The generator has started on the first pull since.

 

[Rivets]

Any time I change points I always spray with brake cleaner, then blow them off with air before installing the cover. That way I know everything is clean and dry.