Points and Condenser Advice

[Vintage Engine Repairs]

Heimannm is right. The primary of the coil, does not get "charged up", it only gets current induced into it as the FW magnets sweep past the coil, so the points only have to be closed briefly as the magnets approach the coil and then open slightly later to cause the spark when the coil current is at maximum saturation.

Thank you, so it’s still the action of the points opening that causes the break in the circuit to collapse the primary? Essentially those points technically could be closed the whole time apart from the split second they open momentarily then?

 

[Old2stroke]

May have to do with design. Could be like new cars with coil each cyl. I hate those.

Interesting how they steadily improved the design on the progression toward electronic ignition.

I have a 3-cylinder 2-stroke outboard (Yamaha) that (I believe) has a small coil for each cylinder (no points, though). I wonder whether the additional coils are mainly to improve ignition, or rather to give you a failsafe to at least "limp" home on 2 cylinders if one of them quits...If it just had one coil and that quit, I guess you could end up walking home.

Coil per cylinder has eliminated the distributor, many people hated those.
With that outboard, without a distributor it couldn't run with one coil, each coil will be firing it's mated cylinder

 

[Mad Professor]

Heimannm is right. The primary of the coil, does not get "charged up", it only gets current induced into it as the FW magnets sweep past the coil, so the points only have to be closed briefly as the magnets approach the coil and then open slightly later to cause the spark when the coil current is at maximum saturation.

Saw coils charge like a magneto ignition.

 

[Mad Professor]

Coil per cylinder has eliminated the distributor, many people hated those.
With that outboard, without a distributor it couldn't run with one coil, each coil will be firing it's mated cylinder

I'd rather buy ONE $30 coil than EIGHT $$$ coils, that don't make much more spark.

IMHO the apex of automotive ignitions was the ONE hot wire Delco distributor with a plug wire to each cylinder. For 8 cyl 9 wires total, a complete ignition with advance features that could be tuned (vac cannistors and adv weights/springs)

Plenty of spark. Simple 1-wire 12v runs it. Enclosed in itself, coil too. Takes 20 minutes to change and time engine with a spare. A spare fits behind a truck back seat ( I have some).

Butt, I suspect you like a rats nest of wires, hoses, and sensors.

 

[Canyon Angler]

With that outboard, without a distributor it couldn't run with one coil, each coil will be firing it's mated cylinder

Interesting, thanks. This particular 1997 outboard has CDI electronic ignition -- does that matter? In other words, could it run with just one coil since it doesn't have a distributor or points? (Not that it matters -- I wouldn't change it -- but I'm just trying to understand a bit more about how it works. The multiple coils always puzzled me, and I just assumed they were a "safety through redundancy" feature ... like 3 carbs for 3 cylinders, which it also has, whereas an old Evinrude twin that I once owned just had one big carb for 2 cylinders.)

 

[Mad Professor]

I'd rather buy ONE $30 coil than EIGHT $$$ coils, that don't make much more spark.

IMHO the apex of automotive ignitions was the ONE hot wire Delco distributor with a plug wire to each cylinder. For 8 cyl 9 wires total, a complete ignition with advance features that could be tuned (vac cannistors and adv weights/springs)

Plenty of spark. Simple 1-wire 12v runs it. Enclosed in itself, coil too. Takes 20 minutes to change and time engine with a spare. A spare fits behind a truck back seat ( I have some).

Butt, I suspect you like a rats nest of wires, hoses, and sensors.

To address the above when I was a poor boy going to college I got a FREE C10 chevy.

Motor was tired a I6-250, I swapped a newer I6-292HD truck motor, that I stripped all and every emmision off of. Went to scrap yard and got a choke carb off a 66 chevy, rebuilt that. Now I'm down to TWO vacuum hoses total (PCV and dist ign), no sensors at all. Ignition runs if it get 12V. No stupid electric choke, a manual one, BTW they work better, IF YOU KNOW HOW TO USE ONE???

That truck was a standard 3 in the tree, I had a spare muncie 4sp for my Camaro. That bolted right up with an 11" clutch. BTW, old GMs 250-454 CI all drivechain stuff pretty much bolted up. Muncie was from a 72 Vette and matted to a hurst shifter (those were worth much more than the truck).

The truck, full size, got 20 mpg loaded with 1/2 cord of wood on the highway. Will new ones?

And if anything went wrong, my small toolbox would fix it (spare dist behind the seat).

I had a fuel pump go. Thank god it was not in the fuel tank! We had dirt bike on back. We took a bike tank and bungeed it in the roof. Gavity fed the carb with a piece of rubber tubing, got to the parts store. Got a $20 mech pump and changed that in 1/2 hour in the parking lot. Try that with a tank mounted fuel pump, done that it SUCKS!!!

HOWS LONG IT TAKE YOU TO CHANGE THE 8 COILS???

 

[Mad Professor]

Coil per cylinder has eliminated the distributor, many people hated those.
With that outboard, without a distributor it couldn't run with one coil, each coil will be firing it's mated cylinder

the old 2 or 4 cyl bike could split duties to 2 or 4 cyl with 1 or 2 sets of points. Simplicity as symmetrical 4-strokes that fire 180 degrees

I never saw that with 3-cyl bikes. Early ones had 3 set of points, later 3 coils.

 

[heimannm]

Patrick McManus - The Human Fuel Pump...

 

[Old2stroke]

the old 2 or 4 cyl bike could split duties to 2 or 4 cyl with 1 or 2 sets of points. Simplicity as symmetrical 4-strokes that fire 180 degrees

I never saw that with 3-cyl bikes. Early ones had 3 set of points, later 3 coils.

To address the above when I was a poor boy going to college I got a FREE C10 chevy.

Motor was tired a I6-250, I swapped a newer I6-292HD truck motor, that I stripped all and every emmision off of. Went to scrap yard and got a choke carb off a 66 chevy, rebuilt that. Now I'm down to TWO vacuum hoses total (PCV and dist ign), no sensors at all. Ignition runs if it get 12V. No stupid electric choke, a manual one, BTW they work better, IF YOU KNOW HOW TO USE ONE???

That truck was a standard 3 in the tree, I had a spare muncie 4sp for my Camaro. That bolted right up with an 11" clutch. BTW, old GMs 250-454 CI all drivechain stuff pretty much bolted up. Muncie was from a 72 Vette and matted to a hurst shifter (those were worth much more than the truck).

The truck, full size, got 20 mpg loaded with 1/2 cord of wood on the highway. Will new ones?

And if anything went wrong, my small toolbox would fix it (spare dist behind the seat).

I had a fuel pump go. Thank god it was not in the fuel tank! We had dirt bike on back. We took a bike tank and bungeed it in the roof. Gavity fed the carb with a piece of rubber tubing, got to the parts store. Got a $20 mech pump and changed that in 1/2 hour in the parking lot. Try that with a tank mounted fuel pump, done that it SUCKS!!!

HOWS LONG IT TAKE YOU TO CHANGE THE 8 COILS???

Don't get me wrong, I am all in favour of old school ignitions and the general approach of keeping things as cheap and simple as possible, unfortunately the trend is in the opposite direction, my 2010 'vette represents the modern design of berserk complications and technology that doesn't improve anything, just make it more expensive and difficult to repair. Do we really need keyless entry and electronic pressure pads instead of door handles?
I was mainly trying to clarify the issue with distributors, if you don't have one, you need a separate coil for each cylinder. The OP with the 2-stroke outboard had electronic coils (so no points) and didn't know why it had 3 coils.

 

[Old2stroke]

Thank you, so it’s still the action of the points opening that causes the break in the circuit to collapse the primary? Essentially those points technically could be closed the whole time apart from the split second they open momentarily then?

Yes, and in a chainsaw engine with points, they are closed for most of the cycle.

Saw coils charge like a magneto ignition.

Coils do NOT hold a charge, they resist any change in the amount of current going through them. Capacitors hold a charge, not coils.

 

[Bob Hedgecutter]

Yes, and in a chainsaw engine with points, they are closed for most of the cycle.

Coils do NOT hold a charge, they resist any change in the amount of current going through them. Capacitors hold a charge, not coils.

That's why you never see a charged coil in a urinal........

 

[Canyon Angler]

That's why you never see a charged coil in a urinal........

Yikes. I think my "outie" just turned into an "innie" with that image.

 

[SteveSr]

Coils do NOT hold a charge, they resist any change in the amount of current going through them. Capacitors hold a charge, not coils.

Both capacitors and inductors (coils) are energy storage devices. Capacitors store energy as an electric field (charge, voltage) on two plates spaced apart by a dielectric. A capacitor will hold a charge depending on the "leakage" of the dielectric.

An inductor will store energy in a magnetic field. Generating the magnetic field requires a current from somewhere (either induced from a nearby changing magnetic field or a current injected into the circuit). To get a current requires a closed circuit. In the case of magneto ignitions this comes from the closed circuit created when the points are closed.

 

[Canyon Angler]

Both capacitors and inductors (coils) are energy storage devices. Capacitors store energy as an electric field (charge, voltage) on two plates spaced apart by a dielectric. A capacitor will hold a charge depending on the "leakage" of the dielectric.

An inductor will store energy in a magnetic field. Generating the magnetic field requires a current from somewhere (either induced from a nearby changing magnetic field or a current injected into the circuit). To get a current requires a closed circuit. In the case of magneto ignitions this comes from the closed circuit created when the points are closed.

I believe welders have "inductors" (big ferrite chokes) that store energy for some small fraction of a second, to improve the welding current by increasing its "inductance."

 

[Old2stroke]

An inductor will store energy in a magnetic field. Generating the magnetic field requires a current from somewhere (either induced from a nearby changing magnetic field or a current injected into the circuit). To get a current requires a closed circuit. In the case of magneto ignitions this comes from the closed circuit created when the points are closed.

In the sense that inductors store "energy", if anyone has ever pulled the power plug on a device running a large inductive load, the resulting nasty arc as you pull the plug is a good demonstration that verifies it.

 

[Mad Professor]

Yes, and in a chainsaw engine with points, they are closed for most of the cycle.

Coils do NOT hold a charge, they resist any change in the amount of current going through them. Capacitors hold a charge, not coils.

Bad wording on my part, coils build a field in the iron core