Access to replace plug wires and remove armature plate on BIG TWIN?

[AlexeiVT]

I'm trying to remove the armature plate on my '64 40HP BIG Twin Evinrude, in order to gain access to the underside, and hopefully remove/replace the plug leads.<br /><br />I've removed the flywheel, and see the coils/points/condensors...but there only appear to be two screws not related to any of these components. I checked the schematics in the manual, and when removed, I get a bit of a wiggle, but not enough to remove the plate.<br /><br />Does some other fastener have to be removed...I was hoping to avoid tampering w/ screws holding the points in place, to avoid having to check/regap them unless need be.<br /><br />Also, one last related question...aside from a digital testing, is there any way to discern whether COILS actually need replacing.<br /><br />I've read that on these older outboards, w/OEM coils, they were notorious for cracking over time.<br /><br />I'm assuming that at some point in time (prior to 10 years ago) the ignition system was addressed. The coils are encased in a plastic material, thus there is no way to really inspect what they may look like underneath.<br /><br />Just trying to debug this motor...quit on my on last outing, and finally today, got around to installing thread inserts into both cylinders, so hopefully tomorrow it'll fire and I can do some more troubleshooting.

 

[OBJ]

Re: Access to replace plug wires and remove armature plate on BIG TWIN?

There should be 4 screws holding the arm plate to the ring retainer. Two of these will be through the coils....they'll be phillips head screws. The other two will be smaller phillips head screws near the points. Remove these screws and the throttle arm retainer and the plate should come off. Check your points also for being burned. Gap is .020.

 

[Paul Moir]

Re: Access to replace plug wires and remove armature plate on BIG TWIN?

The "Test" for those coils is a simple examination. If the outer casing is cracked, they need to be replaced. It is extremely rare to find electrical problems with the coil, so there's no need to bother with the digital multi-meter. <br />It sounds to me like you've got the more modern coils. Sometimes cracks appear in them but it's far less likely than the old coils:<br />

<br />Make sure you use metal core plug wire. Good luck!

 

[Chinewalker]

Re: Access to replace plug wires and remove armature plate on BIG TWIN?

FYI - the four screws that hold the mag plate on form a rectangle. when looking down from above. The two down low, plus the two coil screws closest to the crankshaft.. <br /><br />As Paul noted, it is VERY rare that a coil that isn't cracked actually goes bad.<br /><br />- Scott