amazingly…cheaper for 4 !!

[crosbyman]

https://www.ebay.ca/itm/4x-Ignition-Coi … 0752.m1982

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[seakaye12]

If you want even larger quantities at even better pricing ask them to quote a price for ten units, or 20, or 50. etc.

Can’t hurt assuming you would want to buy in larger quantities if the price justified it.

Others here have done that .

[crosbyman]

running out of oldies to fix …. 🙂

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[westwind]

Remember, if it’s over about $20 you will likely have to pay about $3 each at the post office when they arrive….I found it was cheaper overall to order 1 at a time.

[fisherman6]

The various sellers of these coils seem to be less willing to bargain as they sell more product. They seem to be selling at posted prices and some with a certain percentage discount when you buy over 3 or 4 coils. From there quantity doesn’t seem to matter much if at all. I currently have a set installed in a mismatched piece part built Johnson CD-12. So far they are doing well. I have around 5.5 – 6 hours on them so far between tank time and a little transom time last weekend. Seem good so far. Fit nicely in the magneto. Spark doesn’t seem as strong at low RPM as Prufrex or OMC, but this is only the first motor I have put them in so far it’s running well.
-Ben

OldJohnnyRude on YouTube

[crosbyman]

quote westwind:

Remember, if it’s over about $20 you will likely have to pay about $3 each at the post office when they arrive….I found it was cheaper overall to order 1 at a time.

nope…. they deliver to the door

secondary windings measure about 7K I would have expected a snappy spark (none installed yet) 7Koms is a lot of wire… spooledl over the primaries windings

time will tell but they come in at 42% % of regular cost ( my last OMC coil was 35$ plus 15% taxes at the dealer. 35 + 5.25… $40.25

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[fisherman6]

quote crosbyman:

secondary windings measure about 7K I would have expected a snappy spark (none installed yet) 7Koms is a lot of wire… spooledl over the primaries windings

time will tell but they come in at 42% % of regular cost ( my last OMC coil was 35$ plus 15% taxes at the dealer. 35 + 5.25… $40.25

My secondary winding reading was 6.8 KOhms and 1.8 Ohms on the primary. The secondary to primary ratio is about 3.8:1. My OMC coils show about 4 KOhms on the secondary and about 0.8 Ohms on the primary yielding a 5:1. These coils show somewhat less step up than OMC despite all that wire (which I suspect is VERY light gauge and delicate) in the secondary. I also believe that due to the primary resistance being around twice that of an OMC coil, they require more voltage from the rotating field and therefore more magnet speed (RPMs) to make a spark. I’m no EE, so maybe I’m all wet here. That’s the feeling I’m getting at this time anyway. Yes, they work fine and they are much less expensive than retail on an OMC / BRP coil. I’ll use some of them. We will see if I continue to after some testing.
-Ben

OldJohnnyRude on YouTube

[crosbyman]

?? should’nt the ratio in ohms be 3777 / 1 being 6,800 ohms to 1.8

OMC’s would be 4000 ohhm / .8 ohms = 5000

Yes the ratio is smaller on the cheapies I agree but magnetism/inductance laws were so confusing to me in tech school I gave tech school and went to work for the phone company at 17 ! …where everything worked with…. relays and tubes in the central offices

hey who knows the cheap primaries being 1.8 ohms may cause less current flow on the points when the magnetism field collapses , reducing arching and pitting ❗

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[fisherman6]

quote crosbyman:

?? should’nt the ratio in ohms be 3777 / 1 being 6,800 ohms to 1.8

OMC’s would be 4000 ohhm / .8 ohms = 5000

Yes step up is smaller on the cheapies I agree but magnetism/inductance laws were so confusing to me in tech school I gave tech school and went to work for the phone company at 17 ! …where everything worked with…. relays and tubes in the central offices

hey who knows the cheap primaries being 1.8 ohms may cause less current flow on the points when the magnetism field collapses , reducing arching and pitting ❗

Yes, of course your ratios are correct. I never multiplied mine by 1000 to equal out the KOhms units. 😳 . Still, the voltage step up is considerably lower with the HK coils. I really have no idea how much the extra resistance in the primary winding will have on the erosion of the points. It certainly could make a difference. I don’t know how to mathematically quantify that, but time will certainly give us some answers.

I also agree that the laws of magnetism and inductance are quite confusing. I went into mechanical engineering so there is a whole lot about that stuff I don’t know. I’m curious how these work in another motor. I only have one with them installed currently. The weak spark at low RPM "could" be related to something else particular to this motor. I have a couple others that need coils so I’ll try them in another and see if I have the same results. I will start a new topic and follow up since this one began and a cost per quantity thread. Stay tuned.
-Ben

OldJohnnyRude on YouTube

[crosbyman]

should be interesting…

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