Mercury Mark 5 Coils

[Buccaneer]

Played a little with my newly acquired Mark 5 this morning.
Checked spark…… great on one cylinder,
weak on the other. Pulled the flywheel
and it looks like the coils have been replaced
at one time. Stamped on each coil is " 8 / 90 "
Is that a date stamp?
Are these the correct type coils for a Phelon mag,
or some type of retro-fit?
Noticed that there’s automotive, "carbon" style
spark plug wires (gotta go), so I assume they’ll
remove from the coils okay.
Also notice someone was trying to be creative with
the wiring, as the braided coil ground wire is wrapped
around the laminates several times. There is also a
bare copper wire with it, but can’t tell were it’s terminated
yet. The insulated wires going to the points have been
rubbing on the flywheel hub, and one is showing bare
wire…… may be the cylinder with weak spark.
Haven’t found a picture yet that shows clearly
the original routing of the coil wires, etc.
Anyone have one?
Thanks, Buccaneer

---

Attachments:

Prepare to be boarded!

[billw]

Those are the right coils. The new coils always come with too much wire on them, so something has to be done with it; but that’s not the best job, for sure! Make sure the right primary wire goes to the right set of points: Put the mag at about mid throttle position. Take the plugs out, turn the motor over and note which set of points opens, as which piston nears the top of its stroke. Obviously you want to connect that cylinder’s coil to that set of points. And yeah, loose the carbon wire. Phelon mags are not as strong as OMC mags, even with solid wire; so they need all the help they can get. (Still stronger than Bendix, though.)

Long live American manufacturing!

[RICHARD A. WHITE]

Clean those points, clean those points, clean those points…. the last 4 mags I have went thru had no spark…cleaned the points till they were spotless, and got spark…..3 of the mags were Mercury and one was OMC…just the order they came in…

Oh yeah…. clean the points…LOL

Good luck

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[Buccaneer]

Thanks for the replies! Perhaps I’ll shorten some of those
coil wires, and try to replicate their original routing, if
I can figure out what that may be. Have to see if I have data
regarding the MFD of those condensers.
Was hoping not to open the crankcase as it has good compression
and the rings are loose in the grooves, but if I remember correctly
from my Mk 6 surgery, the lower crank shaft seal has to be driven
out from inside the crankcase…… Is this true on the Mk 5 as well ?
P.S.- I’ll be sure to clean the points!

Prepare to be boarded!

[jw-in-dixie]

Here’s a real handy thing to have for checking coils, without having to disconnect any wires:

http://www.ebay.com/itm/111790074066?ss … 1558.l2649

On eBay, ending today. I have used it for years. You can run the test as long as you like to see if a coil weakens when warm.

JW in Dixie

[Author]

Posts