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No, this is not a real set up at all….
My first thought was that someone mistakenly used driver coils on a conventional mag set up, but that is not the case, there are no spark plug leads coming out of the mag plate. But, on the other hand, I don’t think another driver coil will bolt up to the correct low tension mag plate… The other mounting bosses on the low tension mag plate are for the alternator windings, which has a different bolt set up than the driver coil. So, my only other guess is that someone has attempted to use a conventional universal mag plate so they could bolt up two driver coils. My next question is how this could possibly work, perhaps it never did. The only way I could see this having a chance of working is if the two driver coils are wired in series wired to the points this way. But, I really don’t think the timing would be correct if this stuff was mounted to a conventional universal mag plate… So, perhaps someone machined something up so that two driver coils would mount to the low tension mag plate….
It seems like you have already bought this item, correct? Hopefully you didn’t pay too much for it. I really don’t see how it could work out, but I will “never say never”. It will be very interesting to see how this is actually wired up once you receive it…It certainly can’t hurt to install it to see if you have spark on both cylinders, only takes a few minutes.
Again, this is not a factory set up, unless it is some sort of engineering “experiment” you got your hands on. Having an extra mag plate, provided it is a low tension mag plate and not worn is nice…Two extra driver coils and a wiring harness is nice also.
Very interesting….
OK, this has really got me thinking….Perhaps one end of each driver coil is grounded to the mag plate, this would provide a return path the primary voltage without having to use the other set of points….I can’t wait to hear if this set up actually sparks on both cylinders…OK, as you can tell, I am racking my brain trying to figure out what is going on with that mag plate you have purchased….
Spoke with Dan Anderson who was quick to point out that someone has pressed the driver coil windings onto the conventional universal mag laminations. Dan reminded me that the driver coils are held down with only two screws, these driver coils are held down with three…So, someone has used a conventional universal mag plate, removed the plug wires, installed the low tension wiring harness and pressed the driver coil windings onto conventional universal mag laminations…
I really don’t see how this could possibly work, but I am smart enough “never to say never”. You will know quickly when you install this set up and see what happens….
Dan also reminded me of a simple solution here….Now, you have the conventional mag plate, you could simply remove the driver coils, install conventional coils on this mag plate along with plug wires, remove the external coils, and use it as a universal OMC magneto, like found on the 1972 models…I’m pretty sure the flywheels are the same, but will look into that…
CORRECTION:
Just looked it up, the 73 models use a driver coil with three screws…Looks like the 72 and 73 mag plates supercede to the same number…So, will say that someone just added a second driver coil to the original mag plate…The flywheels are different between the two systems also…. So, we will wait to see if this set up actually produces spark on both cylinders…All I know of this system is what you, fleetwin, and some others have so nicely and thoroughly explained. So I’m learning as I go. I see what Phil says about the flywheel on these having 2 magnets. I looked at the flywheel from my 1973 Evinrude 25 HP that came with the low tension magneto and noticed that. I’m not trying to confuse the issue or say it should be run like this, but just wondering if that setup with the 2 driver coils would work with the earlier flywheel with just one magnet? Maybe that’s how the seller used it?
Not saying that this addresses the weak spark issue, just throwing a couple thoughts out there.
Also, as a side question, why did OMC go to this system in the first place? Was it just an attempt to move the coils out from under the flywheel so they could be replaced easier?
Hello Fleetwin,
Here is the back of the magplate. As per the description” Good parts removed from johnson 20 hp 1975 model 20BA75B, ready to use ! Fit on many model !” I have tried to look for the diagram of it but I could not find it. Go to http://www.marineengine.com and could not find the 20 hp of 1975 model.
All I know of this system is what you, fleetwin, and some others have so nicely and thoroughly explained. So I’m learning as I go. I see what Phil says about the flywheel on these having 2 magnets. I looked at the flywheel from my 1973 Evinrude 25 HP that came with the low tension magneto and noticed that. I’m not trying to confuse the issue or say it should be run like this, but just wondering if that setup with the 2 driver coils would work with the earlier flywheel with just one magnet? Maybe that’s how the seller used it?
Not saying that this addresses the weak spark issue, just throwing a couple thoughts out there.
Also, as a side question, why did OMC go to this system in the first place? Was it just an attempt to move the coils out from under the flywheel so they could be replaced easier?
Well Steve, anything is possible. I guess we will see what happens when he tries out this crazy set up. Your flywheel theory might be the answer, unfortunately E-25 doesn’t have one of each style flywheel to try.
This system was the intermediate stop between regular magneto ignition and CDII, which was introduced in 1977. One of the reasons this system was introduced was to make room for alternator windings under the flywheel…Deleting one of the coils under the flywheel made room for the alternator windings. The low tension mag plates on the 9.9-15, 35, and 40hp models had bosses to accomodate an alternator winding. The 22CI engines used the regular universal mag plate, so the alternator windings would not bolt up on these engines. Don’t know why OMC didn’t leave the universal mag set up in place on the 22CI engines until 1977 though.The picture is the back of the magplate (2 coil setup) that I am going to purchase from EBAY. It is definitely for Canadian market since the seller located in Canada and he parts out his outboard. My current flywheel has two magnet (the same picture from Steve D). So when the flywheel rotate 180, it will generate the charge for both coils and both spark plug fired at the same time???
Base on all the discussions, I hesitate to try this system. I rather stay with original OMC design (1 Driven Coil) so I order the NOS OMC EVINRUDE JOHNSON coil assy 581130 (picture) for $22 and know that I have all completely new (Point, Condenser, Driven Coil and two Charge coils).
How much does he want for the mag plate? I would buy it anyway if it is reasonbly priced… True, you will probably end up staying with the original system, but having the extra pieces is always good… Especially if the mag plate pilot bushing is in great shape… Two extra driver coils, and the all important primary wiring harness….
Would you mind sharing the ebay link with us? I promise not to buy it..
OK, so it seems like you are going to buy it, good… Once it arrives, please take detailed pictures of how the driver coils are connected to the points…Like I say, either the two driver coils are connected in series, with one end of each connected to a set of points. Or, one leg of each driver coil is grounded… If you can, ask the seller if his flywheel has one or two magnets…
It will only take a few moments to just install that mag plate the way it is to see if it sparks. Let us know….
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