68 evinrude 85hp msd conversion

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odave

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Dec 31, 2009
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Hi, well its winter and time to do this project,the amplifier was failing last summer and a few times i barely made it to the dock,,spark would just quit or barely work,,the old rude 85hp pushes my boat great as long as i can get spark to her,,,,, i have got the components msd box and 2 blaster coils and lost my info on the install if anyone has a link or info or any pics of install would be a great help as well as any advice,,,,thanks Dave
 

Willyclay

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Re: 68 evinrude 85hp msd conversion

Dave, welcome to the iboats.com forum. The forum members here are great and can help you with any problem. I installed a multi-spark box and hot coil on my 1962 Johnson 75 which had an automotive-type ignition system with a distributor and points. Your 1968 model should have the CD ignition just like my 1968 Johnson 100. I am interested in your problem because my i00 ignition system is inop also.

While I do not have any suggestions for you about how how to install a MSD box in place of the amplifier, I will share with you what forum guru Joe Reeves brought to my attention before you start swapping parts. Joe said that OMC received a batch of inferior quality wiring harnesses for the 1968 models. Mine has deteriorated so badly that I cannot even test the components. The OEM harness is NLA and I have not found one in the aftermarket. It is possible that your amplifier and other system components may be okay but the wiring harness/shorts may be creating the intermittant problems you described.

If you need an engine wiring diagram, let me know. Good luck!
 

boobie

Supreme Mariner
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Re: 68 evinrude 85hp msd conversion

Have you tried CDI Electronics.com ? At one time when the company was known as Rapair they made up harness for older mtrs.
 

veilside180sx

Petty Officer 1st Class
Joined
May 20, 2008
Messages
202
Re: 68 evinrude 85hp msd conversion

I'll be doing this as well on my '71.

Here's the article I have saved...


(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. In this case of
publishing the following informmation, I (Joe Reeves) am merely an instrument of transference.

I have had several people email me asking how to convert their old OMC CDI 1 to an MSD Ignition. Here is the instructions on how to do this:

CONVERSION TO MSD IGNITION:

The benefits of running the MSD 6A ignition in place of the factory CDI ignition used in 1967-72 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.
 

Willyclay

Captain
Joined
Sep 8, 2006
Messages
3,257
Re: 68 evinrude 85hp msd conversion

Thanks for the super info for all of us with OMC's 1G CD ignition system motors. Moderators, should this be in a sticky?

Now if I can just find a wiring harness, what a Merry Christmas it will be!

EDIT: Just ran the OEM p/n with CDI and they do make one! Now, if I can just convince the First Mate to spend a little more money on my 43 year old gas guzzler.
 
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RichardNaugle

Seaman Apprentice
Joined
Jun 7, 2009
Messages
33
Re: 68 evinrude 85hp msd conversion

hi just having some trouble with my 85 evinrude and was wondering if you ever did the conversion and how it turned out?
 

coolerman2

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Jul 12, 2009
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Re: 68 evinrude 85hp msd conversion

It's winter and time to do motor projects. After studying and researching this mod, I decided to try it and just ordered the parts. According to the instructions in order to drop the output of the 45,000 volt coil so as to not wreck the rotor & distributor, Doug Bryant says the first coil's primary wires need to be "spliced" with a 2nd grounded coil to effectively reduce the output of the 1st coil to 22,500 volts. My question is, by saying "spliced" does he mean wire the 2nd coil in series or parallel with the first coil. With resistive loads, when wired in series, the voltage drops with each load, so that the original 520 to 540 volt output of the MSD box would be reduced to 1/2 that voltage at each coil, so the active coil would only be seeing 260 to 270 volts. Unfortunately, coils aren't resistive loads (but I would think ohms law would still apply).

I talked to a tech at MSD, and off the cuff his response was to wire the 2 coils in parallel (he admittedly wasn't familiar with the technique of wiring 2 coils together and grounding one to reduce the output of the remaining active coil). The more I thought of this, the less sure I was that he was correct because in parallel, each coil will "see" the full 520 to 540 volt output of the MSD box and try to "step it up" by it's 100:1 ratio - yielding about 45,000 volts - which sounds like it could harm the distributor & rotor.

The only thing that makes me think that parallel is OK is that the MSD box is essentially a power limited transformer (stepping 12 volts up to approx 520 volts) and when the load is increased beyond it's design capacity on a power limited transformer - I think the output voltage does drop, but depending on the load vs transformer capacity - I don't know if would fall by 50%.

Anyhow, it's a good brain teaser and I'm looking for other opinions.

Finally, as asked by several other posters....Has anyone really done this modification and posted back here with the results (other than Doug Bryant's original post, saying how well it works)?

Thanks for any help
 

coolerman2

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Joined
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Messages
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Re: 68 evinrude 85hp msd conversion

I finished up this ignition conversion and now I'm trying to get it to run right.

It runs, but the timing advance has to be fully in the retarded position for it to start & run. If I try to advance the timing, even with advancing the carb linkages, it dies.

Also, without changing any of the carb linkage stops, it now idles at 2200 rpm. I haven't taken off the front of the air silencer so I can't see the position of the throttle butterflys, but I'm hoping I can close them off more to slow down the idle. The timing advance is what has me puzzled though. It was too bright out this afternoon to use my timing light, so I can't see where it is timed for when it runs well, but I know if I try to advance the timing towards it's mid-range.....it dies.

Any suggestions?

Thanks

Rick L, Coolerman2

PS: Other notes for anyone trying this conversion:
#1. I wired the 2 blaster coil primaries in series. The instructions on the forum thread don't say whether parallel or series, but series seems to work.

#2. I cut the wire loops for the MSD Box to indicate a 4 cylinder engine, even though our 4 cylinder engines are 2 stroke instead of the 4 stroke engines that the MSD box is designed for. I don't know it this is correct, but MSD wasn't any help on answering the question.

#3. I've kept both sets of points in the trigger circuitry. My understanding is that the 1st set closes the timing circuit and the 2nd set opens the same circuit (or visa versa) and by having 2 sets of points it is only a way of extending the life of the points. I don't know it this is correct. It may be giving me my timing problem since I think it is extending the dwell (plus the MSD box maintains a shower of spark for something like 22 degrees of crank rotation). Maybe that's just too much.

The project is still in the "experiment" stage and it's too early to know it it's a success and whether I'd recommend it for anyone else to try. Unfortunately the feedback from anyone who's completed this conversion has been pretty nonexistant.
 

Willyclay

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3,257
Re: 68 evinrude 85hp msd conversion

Glad to see you are still trying! Hard to disagree with your logic about the parallel vs series wiring of the coils. Maybe you could PM Joe Reeves and see if he has any more info. My reaction to MSD box setup being 4 cylinder is based on my experience with electronic tachometers which require a setting for twice the number of cylinders to get an accurate reading on two-strokes. I'm not sure if that means you should try a setting of two or eight but I think you are on target to question that setting. The points are not an issue for me since my 1968 has a sensor for the trigger mechanism. I can tell you the multi-spark box I ran on my 1962 Johnson 75HP did not alter the timing and idle speed was virtually unaffected. Good luck with your project!
 

coolerman2

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Joined
Jul 12, 2009
Messages
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Re: 68 evinrude 85hp msd conversion

Well I ran the project motor again yesterday and got my timing light hooked up. Again, it only ran with the spark retarded as far back as possible. When I got the light on it, the TDC marking was about a 1/2" to the left of the marker, or in other words, it was indicating that it was firing after TDC.

I decided to pull the flywheel again and check if the points or base plate were screwed up. When I pulled the rotor off I noticed it was electrically blasted by the metal contact point that sends the current to the individual wires as it rotates. It looks like the MSD box is too much juice for our distributors, even with one coil grounded-out like the directions say. I decided to pull all the the MSD stuff off and go back to the stock set-up, since I still have my old amplifier plus another from my parts motor. I'll chalk it up to a good experiment and I gained a lot of experience and knowledge on how the ignition system works (I've taken it apart enough, so I should have learned something).

Anyhow, I'm posting a couple of pictures of the rotor. If you enlarge on your screen, you'll see the damage. In all honesty, some of that damage might of been there prior to the conversion because at that point in my mechanical career I wasn't inspecting everything like I am doing now, so maybe I should have used one of my spare rotors and given it another try, but it's too late now. Anyhow, if anyone wants to buy a MSD 6A box and two blaster coils pretty cheap....let me know.

Rick L
Superior, WI
Coolerman2


DSCF0586.jpgDSCF0585.jpg
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: 68 evinrude 85hp msd conversion

That's because the coils were in series and not parallel. Coils are not the same as resistors and Ohm's law does not directly apply to this AC circuit. There may have been close to 90 kV going through the distributor........
 

coolerman2

Recruit
Joined
Jul 12, 2009
Messages
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Re: 68 evinrude 85hp msd conversion

Thanks for the info. I wish I'd been a little more patient and not torn the MSD stuff off already. It would be worth it to hook the coils up in parallel and pop a new rotor on and see if it made a difference. If I have trouble going back to "stock", maybe I'll give it another try.

Rick L
 

Ron Briz

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Apr 17, 2012
Messages
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Re: 68 evinrude 85hp msd conversion

Hi all
It is very helpful to read all your postings. I recently purchased boat with Evinrude 85hp motor 1969 and privies owner told me to replace amplifier and points but I want to convert this to MSD and after doing some home work I got some interest in Street Fire CDI by MSD. I was wondering if this unit can be used with my motor and why you guys choose MSD 6A unit?
If any body wants more info on Street Fire than O'Rally has catalog for MSD and they have some specs. for this unit.
 

GracieBell1

Petty Officer 2nd Class
Joined
Jan 8, 2010
Messages
152
Re: 68 evinrude 85hp msd conversion

I have a starflite 100 S (1968) I want to fo the MSD and would like a little more info on the two coil hook up. I have a trigger an not points. How would that work or be hooked up? Also, will it not hurt anything to ground out the second coil to the block. I assume this means hook the positive wire to the block? Thanks Stefan
 

bigbadchevy89

Seaman
Joined
May 27, 2006
Messages
62
Re: 68 evinrude 85hp msd conversion

yes someone please explain how to ground this second coil to the block. I am ready to do this conversion on mine I just need to figure out how to ground the coil and where the trigger wire or wires are. Ron Briz also had a good point is the less powerful street fire by msd a valid option. I am also curious exactly how much voltage you drop by grounding out this 2nd coil?

I think a lot of people would like to here these answers not just me.

D.C.
 

Kingdavid1010

Recruit
Joined
Aug 6, 2012
Messages
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Re: 68 evinrude 85hp msd conversion

Coolerman Im interested in buying your msd unit and coils. Do you know if it will work on 1989 evinrude 90 hp v4 2stroke?
 

68glasspar

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Joined
Aug 28, 2024
Messages
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Re: 68 evinrude 85hp msd conversion

I'll be doing this as well on my '71.

Here's the article I have saved...


(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. In this case of
publishing the following informmation, I (Joe Reeves) am merely an instrument of transference.

I have had several people email me asking how to convert their old OMC CDI 1 to an MSD Ignition. Here is the instructions on how to do this:

CONVERSION TO MSD IGNITION:

The benefits of running the MSD 6A ignition in place of the factory CDI ignition used in 1967-72 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.
Sorry for renewing this old thread!
But im trying the same msd conversation and i'm wondering if you had good success with your conversion to msd. I'm trying it on a 1969 85hp evinrude
Thanks!
 

Faztbullet

Supreme Mariner
Joined
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Messages
15,904
Better off using a old automotive amp(Mopar) and coil to keep from burning up rotor
 
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