1968 55hp evinrude upgrade ignition

[trent_tweeter]

Has anyone got the definitive answer as to how to sucessfully convert a 55hp 1968 triple to run with a coil,condenser and ballast resistor setup?
I've viewed many threads on this site and still don't have the full scoup!

 

[clanton]

Re: 1968 55hp evinrude upgrade ignition

Your engine have points??? You just take the old parts off, install new parts same as an old automobile. You will need to insure the switch supplies power to the correct place. You should be able to get a coil with a built in resistor.

 

[freddyray21]

Re: 1968 55hp evinrude upgrade ignition

in theory it will work with points, but I don't know if you will get enough sparks. You need to run a lead from the points to the - side of the coil and 12v's to the + side of the coil. The high tension lead will go to the distributor.

 

[trent_tweeter]

Re: 1968 55hp evinrude upgrade ignition

Thanks clanton & freddyray21 for your reply
Would it be a good idea to get the +12 volts from the starter solinoid and to add a condenser from the neg side of the coil to the block(ground).
I've also read that points tend to arc more with this type of system, any comments?

 

[F_R]

Re: 1968 55hp evinrude upgrade ignition

I have heard of a lot of attempts to do that conversion, but have yet to hear anybody say it worked really well. You have two things working against you. First, the points/cam setup provides some pretty strange dwell. Secondly, the weak spot in that ignition system is not the CD ignition, but that crappy distributor. Even if you do rig up a coil/condenser system, you still have to go through the crappy distributor.

The points work a long time when used to trigger the CD, but from what I've heard, they burn up in short order when used to fire a coil. Have you checked the price of those things lately?

If you still want to try it, the hookup is simple. The wire now feeding the amplifier will go to the coil + terminal. The wire going to the points will go to the coil - terminal. A condenser also goes to the coil - terminal, with the condenser case grounded. Unless you use a 12V coil, you will need a resistor in series with the + lead to the coil. Be sure to report back with the results so the next guy will know how it worked out for you.

 

[trent_tweeter]

Re: 1968 55hp evinrude upgrade ignition

Thanks FR,
would it help the points to use two condensers in parallel?
Yes I am aware of their cost.
With a resistor in series with the + lead to the coil will there be a voltage drop to the coil primary and hence less spark?
Any suggestions as to spark plugs, I've heard that J4C's might be good.

 

[trent_tweeter]

Re: 1968 55hp evinrude upgrade ignition

O.K.
How about using a simple SCR (Silicone Conrolled Rectifier).
The points trigger the SCR therefore very low current passes through the points and the high side of the SCR closes the circuit to the coil and passes the higher current to the primary windings. Yah I know it's sort of reverse engineering as I'm sure the powerpac has an SCR within, but...whatever works, any comments from an electrical engineer out there would be welcome!