Major Differences In Small Engine Coils

[Bret Cahill]

Maybe the voltages vary somewhat for different point and plug gaps but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard, a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the same?

For that matter couldn't a motor vehicle coil work?


Bret Cahill

 

On Thu, 26 Apr 2012 04:11:38 -0700 (PDT), Bret Cahill
<Bret_E_Cahill@yahoo.com> wrote:

Maybe the voltages vary somewhat for different point and plug gaps but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard, a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the same?

For that matter couldn't a motor vehicle coil work?


Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel? Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a low
voltage coil and points mounted on the engine, feeding a more or less
regular ignition coil.

There is bound to be some way to kludge something that will work once
you know what kind of system it uses.

 

[Bret Cahill]

Maybe the voltages vary somewhat for different point and plug gaps but
is it enough to make any difference?  .

Supposedly Honda no longer makes the coils for their 100 outboard, a 2
cylinder 4 stroke engine.  Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the same?

For that matter couldn't a motor vehicle coil work?

Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel?  Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a low
voltage coil and points mounted on the engine, feeding a more or less
regular ignition coil.

That sounds like it.

There is bound to be some way to kludge something that will work once
you know what kind of system it uses.

Actually the part may have been discontinued for the very reason that
the later coils may be easily substituted.

This isn't even an opportunity to jerry rig something together.


Bret Cahill

 

[Ian Field]

"Bret Cahill" <Bret_E_Cahill@yahoo.com> wrote in message
news:b710b382-f457-4e20-a73c-871f31178112@f37g2000yqc.googlegroups.com...

Maybe the voltages vary somewhat for different point and plug gaps but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard, a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the same?

For that matter couldn't a motor vehicle coil work?

Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel? Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a low
voltage coil and points mounted on the engine, feeding a more or less
regular ignition coil.

That sounds like it.

There is bound to be some way to kludge something that will work once
you know what kind of system it uses.

Actually the part may have been discontinued for the very reason that
the later coils may be easily substituted.

This isn't even an opportunity to jerry rig something together.


Bret Cahill

----------------------------------------------------

Since theOP mentions plug gap; its obviously not using surface discharge
plugs (common on marine engines) - they would definately indicate CDI, so
there's some hope they're "regular" coils with points or a TAC module.

Probably worth giving motorcycle coils a try - these come in the 2-lead
(wasted spark) variety used on 4's & some twins, or a pair of single lead
coils as used on twins with 180deg crankshaft.

 

[Ian Field]

"Bret Cahill" <Bret_E_Cahill@yahoo.com> wrote in message
news:1ac4aabe-c61d-49b4-ab3e-bb52cd0e0b31@hq4g2000vbb.googlegroups.com...

Maybe the voltages vary somewhat for different point and plug gaps but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard, a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the same?

For that matter couldn't a motor vehicle coil work?

Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel? Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a low
voltage coil and points mounted on the engine, feeding a more or less
regular ignition coil.

That sounds like it.

There is bound to be some way to kludge something that will work once
you know what kind of system it uses.

Actually the part may have been discontinued for the very reason that
the later coils may be easily substituted.

This isn't even an opportunity to jerry rig something together.

Bret Cahill

----------------------------------------------------

Since theOP mentions plug gap; its obviously not using surface discharge
plugs (common on marine engines) - they would definately indicate CDI, so
there's some hope they're "regular" coils with points or a TAC module.

Probably worth giving motorcycle coils a try - these come in the 2-lead
(wasted spark) variety used on 4's & some twins, or a pair of single lead
coils as used on twins with 180deg crankshaft.

Now they are claiming it was a "rectifier" not a coil.

What would a rectifier do on any ignition system?


Bret Cahill

On a CDI there would be a rectifier between the transistor inverter and the
capacitor, some engines have a high voltage winding on the
alternator/generator stator - but either way the CDI is usually a sealed
unit, so I don't know how exactly they could determine that specifically the
rectifier was at fault.

I did once encounter a Yamaha 125 with energy transfer ignition that had a
diode in the lead from the flywheel coil & ignition coil - failure of that
diode probably would have impaired performance but not stopped it running
altogether.

Maybe if you could post photos of the equipment on a hosting site, and the
link to it here, someone might recognise it and supply some informed advice.

 

[Ian Field]

"Bret Cahill" <BretCahill@peoplepc.com> wrote in message
news:1893cb53-0786-4279-9099-5373d4461910@n8g2000pbv.googlegroups.com...

Maybe the voltages vary somewhat for different point and plug gaps
but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard,
a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the
same?

For that matter couldn't a motor vehicle coil work?

Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel? Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a
low
voltage coil and points mounted on the engine, feeding a more or
less
regular ignition coil.

That sounds like it.

There is bound to be some way to kludge something that will work
once
you know what kind of system it uses.

Actually the part may have been discontinued for the very reason that
the later coils may be easily substituted.

This isn't even an opportunity to jerry rig something together.

Bret Cahill

----------------------------------------------------

Since theOP mentions plug gap; its obviously not using surface
discharge
plugs (common on marine engines) - they would definately indicate CDI,
so
there's some hope they're "regular" coils with points or a TAC module.

Probably worth giving motorcycle coils a try - these come in the
2-lead
(wasted spark) variety used on 4's & some twins, or a pair of single
lead
coils as used on twins with 180deg crankshaft.

Now they are claiming it was a "rectifier" not a coil.

What would a rectifier do on any ignition system?

Bret Cahill

On a CDI there would be a rectifier between the transistor inverter and
the
capacitor, some engines have a high voltage winding on the
alternator/generator stator - but either way the CDI is usually a sealed
unit, so I don't know how exactly they could determine that specifically
the
rectifier was at fault.

This was just another flywheel magneto/alternator to charge up a
battery to power running lights, about 60 watts, completely
independent of the ignition system.

I did once encounter a Yamaha 125 with energy transfer ignition that had
a
diode in the lead from the flywheel coil & ignition coil - failure of
that
diode probably would have impaired performance but not stopped it running
altogether.

Maybe if you could post photos of the equipment on a hosting site, and
the
link to it here, someone might recognise it and supply some informed
advice.-

http://data.sohc4.net/Tech/HondaMES/HondaMES5.PDF

The first time I saw the 1978 BF100 outboard was wired up like the
system of Fig 48.

If it is the coil you need, a lot of small motorcycles use the energy
transfer type.

CDI has probably become more common on modern models, but for 80's models
most small 2-strokes used energy transfer and some small 4-strokes like the
Honda C50 & C70 step-through's (the C90 had Kettering battery-coil ign).

Another group you might find some help on is sci.electronics.repair -
strictly its for electronic equipment, but there's plenty of knowlegeable
people there.

 

[Bret Cahill]

Maybe the voltages vary somewhat for different point and plug gaps but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard, a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the same?

For that matter couldn't a motor vehicle coil work?

Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel? Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a low
voltage coil and points mounted on the engine, feeding a more or less
regular ignition coil.

That sounds like it.

There is bound to be some way to kludge something that will work once
you know what kind of system it uses.

Actually the part may have been discontinued for the very reason that
the later coils may be easily substituted.

This isn't even an opportunity to jerry rig something together.

Bret Cahill

----------------------------------------------------

Since theOP mentions plug gap; its obviously not using surface discharge
plugs (common on marine engines) - they would definately indicate CDI, so
there's some hope they're "regular" coils with points or a TAC module.

Probably worth giving motorcycle coils a try - these come in the 2-lead
(wasted spark) variety used on 4's & some twins, or a pair of single lead
coils as used on twins with 180deg crankshaft.

Now they are claiming it was a "rectifier" not a coil.

What would a rectifier do on any ignition system?

Bret Cahill

On a CDI there would be a rectifier between the transistor inverter and the
capacitor, some engines have a high voltage winding on the
alternator/generator stator - but either way the CDI is usually a sealed
unit, so I don't know how exactly they could determine that specifically the
rectifier was at fault.

This was just another flywheel magneto/alternator to charge up a
battery to power running lights, about 60 watts, completely
independent of the ignition system.

I did once encounter a Yamaha 125 with energy transfer ignition that had a
diode in the lead from the flywheel coil & ignition coil - failure of that
diode probably would have impaired performance but not stopped it running
altogether.

Maybe if you could post photos of the equipment on a hosting site, and the
link to it here, someone might recognise it and supply some informed advice.-

http://data.sohc4.net/Tech/HondaMES/HondaMES5.PDF

The first time I saw the 1978 BF100 outboard was wired up like the
system of Fig 48.

I'm not 100% sure, however, the original system wasn't the low
tension
magneto system of Fig. 47 and a shop / previous owner confused the two
systems and wired the point/cap wire to the same connector as the
magneto output by mistake.

The top of the new coil is mounted to the engine by a bolt going
through the center lug and then through a laminated 1 cm^3 cube that
looks like it could be an insulator.

That would explain how the magneto could put out a few volts on an
analog multimeter yet the secondary puts out nothing. The primary
coil never has any way to complete a circuit.

That's one easy to test theory.

On the other hand the system would be correctly wired up but since the
original coil was discontinued the new coil could be for different
system. The 1 cm^3 cube is in fact an insulator that prevents the
primary from being grounded.

(I'm good at coming up with a multitude of theories, not all suspect,
when trouble shooting.)

I get ball park range resistances for the coil, 0.75, 3 and 30,000
ohms between the 2 ark plug wires. By tapping the condenser with 12
volts DC at 2 - 3 hz the volt meter goesp more than tapping w/o the
cap.

I like to try the easy stuff first so I won't worry about the coil and
cap just yet.

There are still other easy problems to be checked, i.e., shorts and
broken wires, bad kill button, points open to 0.017 which is a little
high compared to some systems. Maybe lower that to 0.014 to make sure
it is closed some of the time.


Bret Cahill

 

[Bret Cahill]

Maybe the voltages vary somewhat for different point and plug gaps
but
is it enough to make any difference? .

Supposedly Honda no longer makes the coils for their 100 outboard,
a 2
cylinder 4 stroke engine. Isn't it likely that other small engines,
say from riding lawnmowers, use coils that are pretty much the
same?

For that matter couldn't a motor vehicle coil work?

Bret Cahill

I wouldn't jump to that conclusion without doing some poking around.

Does it use a separate coil or is it a magneto mounted on the
flywheel? Does it use a transistor switched coil high turns ration
pulse transformer or inductive kick type?

There's also something called "energy transfer magneto" which is a
low
voltage coil and points mounted on the engine, feeding a more or
less
regular ignition coil.

That sounds like it.

There is bound to be some way to kludge something that will work
once
you know what kind of system it uses.

Actually the part may have been discontinued for the very reason that
the later coils may be easily substituted.

This isn't even an opportunity to jerry rig something together.

Bret Cahill

----------------------------------------------------

Since theOP mentions plug gap; its obviously not using surface
discharge
plugs (common on marine engines) - they would definately indicate CDI,
so
there's some hope they're "regular" coils with points or a TAC module.

Probably worth giving motorcycle coils a try - these come in the
2-lead
(wasted spark) variety used on 4's & some twins, or a pair of single
lead
coils as used on twins with 180deg crankshaft.

Now they are claiming it was a "rectifier" not a coil.

What would a rectifier do on any ignition system?

Bret Cahill

On a CDI there would be a rectifier between the transistor inverter and
the
capacitor, some engines have a high voltage winding on the
alternator/generator stator - but either way the CDI is usually a sealed
unit, so I don't know how exactly they could determine that specifically
the
rectifier was at fault.

This was just another flywheel magneto/alternator to charge up a
battery to power running lights, about 60 watts, completely
independent of the ignition system.

I did once encounter a Yamaha 125 with energy transfer ignition that had
a
diode in the lead from the flywheel coil & ignition coil - failure of
that
diode probably would have impaired performance but not stopped it running
altogether.

Maybe if you could post photos of the equipment on a hosting site, and
the
link to it here, someone might recognise it and supply some informed
advice.-

http://data.sohc4.net/Tech/HondaMES/HondaMES5.PDF

The first time I saw the 1978 BF100 outboard  was wired up like the
system of Fig 48.

If it is the coil you need, a lot of small motorcycles use the energy
transfer type.

CDI has probably become more common on modern models, but for 80's models
most small 2-strokes used energy transfer and some small 4-strokes like the
Honda C50 & C70 step-through's (the C90 had Kettering battery-coil ign).

Another group you might find some help on is sci.electronics.repair -
strictly its for electronic equipment, but there's plenty of knowlegeable
people there.

Thanks.


Bret Cahill