1970 Johnson 60 Hp w/ MSD Ignition - A Success Story

[maxpipefill]

Hey,

I was never a boat guy, but I always wanted to be a boat guy so I decided to buy an old aluminum StarCraft Super Sport boat with an old 1970 Johnson 60 Hp motor.

The motor suffered from a no spark condition. I quickly found out that the amplifier module on these motors were sensitive to voltage and prone to failure. I purchased a replacement amplifier and it failed within hours due to insufficient voltage from a discharged battery.

Loosely following the popular instructions online I swapped my old unreliable amplifier for an MSD 6A. You can split the voltage by adding a second coil because the MSD outputs to much voltage and will damage the distributor. The online instructions called for new coils wired in series but to save money I used two Johnson coils I had on hand. coil number one secondary terminates at the distributor and instead of running the secondary of coil 2 to ground I removed the wire.

Its not pretty and i had to relocate a few things but I have never had an issue with this motor since. I'm continuously removing the flywheel and stator looking for signs of damage or melting from heat associated with the additional voltage and I am always surprised when everything looks perfect. I preformed this swap in early January of 2017 and have many hours on the motor since.

I see a lot of the threads associated with this swap that end with "can anybody confirm" or "has anybody had long term success with this" and thought I should share my success story.

 

[F_R]

Interesting story. Frankly, I've never heard of too much voltage, and seriously doubt it. In theory, the voltage only rises till it reaches whatever it takes to jump the plug gap (or goes somewhere else), then it's gone. But I won't dispute your story.

 

[maxpipefill]

Some of my numbers could be off, but the MSD ignition produces approximately 500 volts and after the coil it steps up to 45,000 volts. The old pulse pack put out 250-300 volts and puts out 30,000 volts after the coil. I think the coil ratio was 1:100. The plastic distributor cap will not handle the extra voltage supplied by the coil, so the 2nd coil is wired in series, the MSD voltage has been cut in half to approximately 22,500 volts according to Kirchhoffs Voltage Law.

 

[F_R]

Whatever you say.

 

[F_R]

Heh, at least you got me to get out the books and refresh my memory of what Kirchoff's Law says. But I'm not going to argue the point here.

 

[tblshur]

maxpipefill thank you for sharing. very informative and got this old brain thinking again.thanks again keep them com:tea::tea:ing:joyous:

 

[Lightwin 3]

Good for you. I have to admire your thought process and success!:hail:

 

[maxpipefill]

Thanks for the support. Though I did days of researche in order to completely understand the parts involved and how they could safely work together the credit goes to the original poster and his instructions mentioned on this forum in the past and found elsewhere online.



(Conversion To MSD Ignition)
(By Doug Bryant)

This article was written by Doug Bryant and posted on one of the marine website forums
on Monday, July 23, 2007, at 10:49 PM. Full credit is to go to Doug Bryant.


CONVERSION TO MSD IGNITION:

The benefits of running the MSD 6A ignition in place of the factory CDI ignition used in 1967-72 Johnson and Evinrude outboards are numerous.
1) The MSD box is more durable. MSD boxes work with as little as 5 volts or as much as 18 volts. Factory box will quit working if charging system is faulty.

2) Factory box sparks one time while MSD ignition box sparks through 20 degrees of crank rotation.

3) MSD box is much cheaper than factory box and MSD box can be purchased from most auto parts stores. Factory boxes are becoming harder to find, as they are no longer in production.

4) An outboard with the MSD box is much easier starting, idles better, and has improved throttle response.

PARTS REQUIRED:

A MSD 6A ignition box and (2) high vibration coils. The coils need to be high vibration, as oil filled will break down from the engine vibrations. The 6A box is currently offered on summitracing.com for $179.00 and the coils are $40 a piece. Total parts cost= $260.00. Cost of a factory box is $250 to $350.

INSTALLATION:

The installation is very straightforward. Follow installation instructions per MSD standard ignition hook up. Heavy red and heavy black wires to 12v positive and 12v ground. Thinner red wire connects to a 12v switched power source. Now here is where this gets a little interesting. The orange and black wires connect to the coil; orange is positive and black negative. However, these wires need to be spliced so that both coils can be hooked up. One coil is connected to the distributor cap and the other coil has its coil wire grounded directly to the block. The reason for this is simple: The MSD ignition produces approximately 45,000 volts. The old system puts out 30,000 volts. The distributor cap will not handle the extra voltage so the 2nd coil is wired in and by grounding it out, the MSD voltage has been cut in half to approximately 22,500 volts. Finally the white wire is connected to the points under the cap. That completes the installation wiring. The MSD box can be mounted directly to the motor or it can be mounted in the boat somewhere. The installer will have to figure out the best locations for both coils to mount as well.

FINAL THOUGHTS:

By upgrading to the MSD system, the motor will perform well for many years to come. The MSD system dramatically improves the overall performance of these motors. The MSD box must be a 6A. MSD offers some less expensive ignition modules but they do not work. The box has to be a true CDI unit. Also, the MSD box will work on any 4, 6, or 8 cylinder 4-stroke engine. However, it will also work on 2 stroke outboards with 4 cylinders and it should also work on 3 cylinder models as well. The author has only used the MSD system on a V4 Johnson 85hp 1970 outboard. It worked great!!
Occasionally the other method of converting these motors to standard 12v inductive ignition is offered as an alternative to the CDI ignition. This conversion is done by adding a condenser and a ballast resistor to the ignition system and using the coil to store up the ignition energy. I have never done this conversion personally but I have been told it would work. However, there is one problem that occurs with this conversion. When this method is used it will directly cause much more wear and tear on the points. This is because when the CDI system is not used more voltage goes through the points, which shortens their lifespan. These points are no longer available and they are harder and harder to find. So, this should be considered when deciding which conversion to use.

 

[TTFullTimer]

I have another boat in a long string of boats. Staying on Lake Huron so I picked up an older tri hull with a 1970 60 HP Johnson. Previous owner got a new CDI ignition and "friends" helped since he had little skills to tackle the job. One stripped spark plug hole later the poor guy just gave up and decided to sell. I got the ignition hooked up properly and it fired. The service manual arrived and it was time to check step by step syncs and the induction/fuel system. Everything was off and subsequently got adjusted by the book. I had read a number of threads about the CDI and the true upgrade using the MSD system. Found one on eBay, along with a double coil. With the CDI starting was a spray of starter fluid when cold. Then it would run on the muff. First trial with the MSD system and it started immediately cold. Now comes the fun part on the water getting all the idle and low speed needles set. Center first then the upper and lower one at a time. Got it.

 

[atengnr]

Hi, how did the last conversion go? I have a 68 55hp and want to convert the ignition as well. Is the MSD upgrade and big improvement on simply putting in a coil and condenser??

Thanks. I am very curious to hear how your conversions went!

 

[jbcurt00]

Hi, how did the last conversion go?

I am very curious to hear how your conversions went!

Its been well over a year since anyone last posted here.

Unlikely they will get or reply to your query

Please observe the no new posts after 90days of inactivity rule.

Closed