Home spun coil replacement on early (Fat 50) John/rude Outboards

liliwaste

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latest 50 HP 007.jpgHas anyone ever experimented with replacing the original ignition coil on a fat 50 Evinrude/Johnson Outboard with an automotive ignition coil and then piping the high voltage through the cap on the bypass line to the rotor. Bought this motor and have pictures of he conversion but haven't tried to fire up the unit yet.
:D

Thanks in advance
 

HighTrim

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

Did you use the stock cap?
 

Chris1956

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

I did that coversion when I found out the cost of the replacement ign coil. I used a ford coil and condenser. I drilled the dist. cap to accept the wire from the coil. I needed to hit the back of the brass brush holder to make the connection. You look to have some non-std dist. cap, but it looks correct. In theory you will want to use 12VDC to the coil when cranking the motor with the starter, and then drop the voltage to 8VDC when running normally.
 

Rayzor

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

You can cut the voltage by using a mopar style ballaist resistor. It has dual poles. One provides a full 12 volts for cranking, the other drops the voltage down to like 6-7 volts. You can get them at any parts house for a couple bucks. Just tell them you have a 76 Dodge truck, and that will get you one.
 

liliwaste

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

Did you use the stock cap?

Hi there, first thing first, thanks for the feeed back. I did remove the magneto to see what the previous owner did to make the unit run, I can send pictures if you would like but the inside of the cap had some heavy carbon tracking that appeared to have been repaired but not to any permanent degree. The capacitor was not a stock Evinrude capacitor and I feel like it was off from some car to have matched the coil and the number of cylinders. The points were the corrrect points for that magneto. One thing that I thought was totaly strange was there was a very heavy oxide, brown in color on all of the point contacts and so thick there would have been 0% chance that they would have conducted any current. The guy drilled a hole where he carbon idler brush is located and kept the brush and screwed on the outside of the cap a tower from what looks like it came from an old spark coil. Then he sealed the tower and the carbon traces with a similar black plastic to maintain electrical integrety. I think this was a interesting way to keep this old motor running and as long as the engine had a charging system I think that it could worked Ok, I don't know what the crud on the points is, it kind of reminds me of heavy lime build up.
Thanks for the responce
 

liliwaste

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

Hi there, first thing first, thanks for the feeed back. I did remove the magneto to see what the previous owner did to make the unit run, I can send pictures if you would like but the inside of the cap had some heavy carbon tracking that appeared to have been repaired but not to any permanent degree. The capacitor was not a stock Evinrude capacitor and I feel like it was off from some car to have matched the coil and the number of cylinders. The points were the corrrect points for that magneto. One thing that I thought was totaly strange was there was a very heavy oxide, brown in color on all of the point contacts and so thick there would have been 0% chance that they would have conducted any current. The guy drilled a hole where he carbon idler brush is located and kept the brush and screwed on the outside of the cap a tower from what looks like it came from an old spark coil. Then he sealed the tower and the carbon traces with a similar black plastic to maintain electrical integrety. I think this was a interesting way to keep this old motor running and as long as the engine had a charging system I think that it could worked Ok, I don't know what the crud on the points is, it kind of reminds me of heavy lime build up.
Thanks for the responce

Just saw the post from the gentilman who did the conversion, thanks much and yes I saw the ballast resistor, did you ever get the motor to run? I thought you could pick up the 12 volts from the choke circuit, really appreciate all the input!
 

boobie

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

Same question, did the mtr run ?? And if it did, how good ??
 

Chris1956

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

My Fatty did run on the Ford coil and condenser. I did not have a working generator, but the current draw was small, so you could run it all day, and then charge the battery at night.

I eventually found a used OEM coil and converted back to magneto ign.
 

liliwaste

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

My Fatty did run on the Ford coil and condenser. I did not have a working generator, but the current draw was small, so you could run it all day, and then charge the battery at night.

I eventually found a used OEM coil and converted back to magneto ign.

Hi I must appologize I am not sure that this info will be received but if this is the same motor boy do I have some questions for you.
1 This engine has a replacement set of Johnson heads, how come?
2 Engine looks very good like it had little time in the water
3This engine has a brand new ignition coil but I didn't see a make or manufacturer
By the way you did a superb job on mounting all the hardware.
4 This engine is a 1959 Starflite
5 What caused all the carbon tracking inthe dist.
Thanks ever so much
 

Chris1956

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Re: Home spun coil replacement on early (Fat 50) John/rude Outboards

That is not the same motor I had, but they are pretty common.
I have no idea why it has Johnny heads. Maybe the originals went bad or they installed Johnny heads at the factory, or someone switched cowlings.
I never had any buildup of carbon in the distributor cap, so I cannot guess what/why you have.
 
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