Need replacement coil help

shuston377

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HELP!!! I have a 1973 Chrysler 70HP outboard (Model 707HE) that had the Magnapower Ignition System. I bought the motor from a gentleman who unfortunately can no longer be contacted. The engine ignition coil was swapped out to a standard 12V automotive canister coil with the ceramic ballast resistor (two prongs and about 2 inches long) however it was not being used with the coil (internal resistor on the coil I would assume.) The engine was running fine and then had absolutely no power at WOT. The canister coil was so hot you couldn't touch it and I can get no real ohms readings from it. Mechanic says it's bad. Ok no problem I thought, I will just get a new one. That's where the problem comes in. I need to find a 12V canister coil that is the right ohms to supply the proper voltage so as to not burn up my points. I would prefer to not use the external ceramic ballast resistor for two reasons; (1) I don't know if it is any good, and (2) it wasn't being used prior to the failure of the current coil. I am trying to make sure I put this thing back to the way it was prior to the failure in case it relies on other changes I am unaware of in the ignition system. So my question is this, please tell me someone on here has seen this before and can tell me what type of replacement 12V canister coil I can purchase to put the engine back to operating condition the way that it was prior to the coil failure. Do I need one with an internal ballast resistor, no ballast resistor is necessary (although I doubt this as you would be supplying the full 12 volts constantly and thereby burn up your points), or do I have to use a 12v coil and the external ceramic ballast resistor???? I would just get the info off of the old coil, as it was working just fine, but unfortunately it has been on there a while and the info has been rubbed off by the bracket that holds it on. I am assuming that it had an internal ballast resistor since it wasn't hooked up to the external one. Any help would be greatly appreciated. I have been all over the web and even talked to Mallory / Accel as to which one of their canister coils would work and they were not able to assist me.

Thanks in advance to anyone that can help!
 

mrwiggles2

Seaman
Joined
Aug 26, 2008
Messages
70
Re: Need replacement coil help

HELP!!! I have a 1973 Chrysler 70HP outboard (Model 707HE) that had the Magnapower Ignition System. I bought the motor from a gentleman who unfortunately can no longer be contacted. The engine ignition coil was swapped out to a standard 12V automotive canister coil with the ceramic ballast resistor (two prongs and about 2 inches long) however it was not being used with the coil (internal resistor on the coil I would assume.) The engine was running fine and then had absolutely no power at WOT. The canister coil was so hot you couldn't touch it and I can get no real ohms readings from it. Mechanic says it's bad. Ok no problem I thought, I will just get a new one. That's where the problem comes in. I need to find a 12V canister coil that is the right ohms to supply the proper voltage so as to not burn up my points. I would prefer to not use the external ceramic ballast resistor for two reasons; (1) I don't know if it is any good, and (2) it wasn't being used prior to the failure of the current coil. I am trying to make sure I put this thing back to the way it was prior to the failure in case it relies on other changes I am unaware of in the ignition system. So my question is this, please tell me someone on here has seen this before and can tell me what type of replacement 12V canister coil I can purchase to put the engine back to operating condition the way that it was prior to the coil failure. Do I need one with an internal ballast resistor, no ballast resistor is necessary (although I doubt this as you would be supplying the full 12 volts constantly and thereby burn up your points), or do I have to use a 12v coil and the external ceramic ballast resistor???? I would just get the info off of the old coil, as it was working just fine, but unfortunately it has been on there a while and the info has been rubbed off by the bracket that holds it on. I am assuming that it had an internal ballast resistor since it wasn't hooked up to the external one. Any help would be greatly appreciated. I have been all over the web and even talked to Mallory / Accel as to which one of their canister coils would work and they were not able to assist me.

Thanks in advance to anyone that can help!

You should PM Frank, I think he will undoubtedly know. Mike here on the forum had me use Mastertech Outboards and they came through really well for me obtaining seal/pump kits for my 70hp 707HF model. Mine is also a 1973. Our engines are almost if not identical. Here is the coil that is in use on mine with the Magnapower ignition. HOpe this helps you. I found this place to have decent prices and very fast shipping.

http://www.maxrules.com/fixforcelectric.html#1825475
 

Frank Acampora

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Joined
Jan 19, 2007
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12,004
Re: Need replacement coil help

Chrysler used the term Magna-Power quite loosely to describe several ignition systems.

The really poor system was the magna-Power II which failed quite regularly. However, my manual does not show it at used on the '73 engines at all.

The Motorola Magna-Power was in some respects a better system, even though it was an older design, but it could fail as any electronic device may do.

So: It appears that your 70 Hp engine may have been originally fitted with Motorola and when it failed, the previous owner did not want to spend either the money to buy a new CD or the time to find one. Thus: he retrofitted to a coil and points system. If the voltage regulator/rectifier is a finned aluminum black box mounted on the starter mount, then for sure the original equipment was Motorola. If it has the big square selenium rectifier with a trip regulator, then it may not have been Motorola but may have been the Delta system.

All this is to point out that you CAN refit to original Motorola or Delta and gain the benefits of higher voltage ignition, and not too expensively. All you really need is the CD unit because the points were used to signal it, and spark was fed into the distributor as it is now. Since points are now used to only signal and don't carry heavy current, they will last forever. Want to go whole-hog? Find an electronic distributor with the electric eye. It will be more precise than points.

NOW!

Since automobile battery voltage during starting drops to about 9 volts, standard auto coils are 9V coils with a ballast resistor that is bypassed during starting. This ensures full design voltage to the coil at all times. However, this does not always hold true for smaller marine outboards, so a 12 volt coil without a ballast resistor can be used. Properly set-up, a 12 volt system will not burn the points because the condenser absorbs the voltage surge when the points open and close and prevents arcing.

IF you want to re-fit to original equipment, then contact The Chrysler Crew and advertise for the part you need. If you wish to remain with points and coil, a good quality 12 volt coil should do, perhaps a racing coil might be better. Ask at the local speed shop.

I did set up one 75 with points and coil ignition but I was NEVER very happy with it. It always ran rough and never idled well no matter how much I messed with it. Even the old school electronic ignition was way better in all aspects of performance. So, if you do not immediately need to use the engine, I would recommend hunting up the Motorola CD box.
 

shuston377

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Mar 24, 2009
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Re: Need replacement coil help

Sorry for the late reply, unfortunately I have been under the weather. Thanks to all who responded...with a special thanks to Frank. I really appreciate the full explanation that you provided. So far that has been way more informative than I have gotten anywhere else. You guys on here are great. Thanks again.

Scott
 
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