Atom points eliminator failure mode..

[rudderless]

I have a couple of Atoms on a 9.9/15omc bought last year as nos. End of 2017 season it started to run real funky after 2000 rpm or so. Runs good until then. It runs after 2000rpm or so like a point system without condensers. Its like a cap opens after 2000 rpm. Like as in scattered timing. I haven’t started to diagnose the electrical but reed and carb are good.

Anybody have an Atom go down on them and how did it act? …

[Mumbles]

I’ve never had an ATOM go bad but it’s the Nova II’s which have given me trouble. When the Novas go, it’s like turning a switch. The affected cylinder goes dead, right now, with no warning.

I’d replace the plugs with NGK’s and thoroughly check all of the wiring and coils before suspecting the ATOMS.

[rudderless]

Thanx Mumbles. I bought them hoping to loose 5 lbs, double the hp and cut fuel usage by half..obviously im kidding but it didn’t really run any different. I am familiar with the point system as that is all we had on snowmobiles of the 60s and 70s. The motor is torn down in my business office at the moment and will put the point system back in as its not a big deal to do. I did see the novas have been redesigned according to advertisements? I was going to do the Debe thing and make a couple but business has picked up so no time for that.

I’m on a river that has a 14′ falls at one end and a 24′ dam to go over at the other. Those atoms are always in the back of my mind when ever I’m near the dam or the falls. When i installed the atoms I put on new Purfex coils while they were still available. I know that really doesn’t mean there good but the point system will prove bad or good. I’ve got 200 hours on the atoms. They are mounted on the outside so they really don’t see much heat.

It sure runs odd after 2000 rpm though..

[rudderless]

I put the points back in during the game. Half assed the point gap and I get good spark at about 100 rpm. I do have the electric start driver coil. I guess I’ll remount the powerhead and wait for warmer weather to barrel test. I’ll strobe set the points then.

[Mumbles]

quote rudderless:

I do have the electric start driver coil.

Is this motor electric start with an alternator?

See the note at the bottom of this instruction sheet.

---

Attachments:

[rudderless]

No, the flywheel has 2 pr of mags…non-electric charging wheel. I got the higher output driver coil to offset the inherent conductivity (about 1500 ohms) of the atoms when they open. Yea..the recoil will snap back sometimes cause of the good low speed spark. If it wasn’t for the crappy carb it would idle at 100rpm.

I did throw the dvm on the atoms and they read different by 1000ohms or so..I know thats not the test but one is still good. Which one who knows..need to find the schematic again.

Ran good for 200 hours before this..

[debe]

This is whats in the original Atom module.

[debe]

This is the circuit with a added Mosorb to protect from high voltage spikes.

[Pete]

Not related to your engine but this may explain strange operation over 2k revs. I tried the Nova II’s in my 2 cylinder Yamato 80 race outboard that is set up with a locked magneto once timing is set where desired. I installed the Nova’s outside for excellent ventilation and to stay away from heat. I set up the mag timing with a inductive strobe light using a drill to rotate about 400 revs. Then started the engine and it cranked right over that is a good sign 😀 . But when the timing was checked at higher revs it was seriously advanced and was not where set with the drill rotation (again magneto locked from movement) 😮 ❓ If you do use any of these chips Nova, Atom, etc. run the engine and look at what the timing does and if in spec. These chips are simple triggers based on a fixed voltage in the primary circuit, there is supposedly no timing advance curve built into them, what gives ❓

[rudderless]

Thanx Debe…I lost your info when my puter puked. Like I said it ran good for about 200 hours then all of a sudden it ran like a point system with a bad cap. I have a little used log splitter that I have to pull the wheel and clean the points before I can run it about every time. I’ll probably put the good atom in it to avoid the point issue.

I’ve got the points back in my outboard and will probably keep them in. Ran fine with them but decided to fix what wasn’t broke.

zul8tr..I suspect there are some unit specific issues with some ignition systems that render the atoms not usable? I’m probably stating the obvious..

[Author]

Posts