Wobbly Armature Plate 1975 9.9Hp Evinrude

[OptsyEagle]

I have a question about this procedure:

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Magneto Armature Plate)
(J. Reeves)

If the armature plate has a a loose fitting, wobbling motion (the plate that the points, coils etc are attached to), it is usually caused by a slightly worn support ring. This allows the point setting to change erratically as the armature plate turns.

The cure is to remove the armature plate so that the support which is attached to the powerhead with 4 screws is visible. Then, with a screwdriver and hammer, or some tool of your choosing, and looking straight down at the support ring, make an indentation at what would be called the 12, 3, 6, and 9 O'clock positions. Install the armature plate and check for a smooth turning wobble free movement.

You may need to do that procedure a few times to obtain the proper fit (not too tight, not too loose), but it's worth the effort.

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When I remove the armature plate and then remove the plastic bearing ring, I am not sure if I am supposed to put the indents on the level of the support ring where the 4 screws are or in the edge area where the plastic bearing ring goes (slightly elevated and eventually covered by the plastic bearing ring). The other alternative is the 2 inch diameter metal material that surrounds the armature cam that also looks like it supports the armature plate in he center, as well.

The area where the 4 screws are, on the support plate, seems too low and it doesn't seem to me that it actually touches the armature plate and I am not sure 4 indents would do anything there. Perhaps I am missing something with this procedure. I don't want to bang an indent in the wrong area. Appreciate some help

 

[OptsyEagle]

OK, so I found a post from Kbait a while back that tends to explain this procedure with a little more detail:

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from Kbait:

Armature plate is held onto the retainer (below armature plate bearing and support ring) by 5 phillips head screws. Loosen all of 'em and pull their threads up into the armature plate itself, which un-hooks it from the retainer. Lift the armature plate off the 'boss' at it's center (boss is on top of powerhead w/crankshaft going through it). Now, pull that plastic armature plate bearing off of it's holder (support ring) and set it aside. Place the armature plate back onto the 'boss' and check lateral play.. turn a bit and check again. If it moves laterally, what you do next will take up the slack space. Again remove armature plate and look at the 'boss' on top of powerhead. It's round, and the bearing surface is about 1/4" in height. Take a sharp centerpunch (or a screw, nail, etc) and 'peen' 4 spots halfway up the height of the sides of the boss at the 12, 3, 6, and 9 o'clock positions. What you're doing is making a little 'wave' of metal rise up around your punch marks, and that metal will take up the slack space between the 'boss' and your armature plate's center bearing surface. Start w/small 'peens', replace armature plate and check play (also, turn the armature plate to check for too much binding). If it still has play, peen the same exact spots again, and re-check play until there's no play left. Don't peen so much as to make the armature plate bind too much when turning(creates stiff throttle).. a little resistance is fine.

Now, reassemble. *The plastic armature plate bearing ring is dry fitted.. wipe all grease/oil off of that bearing, it's support ring, and the underside of the armature plate where it rides before reassembling*. Also, you can use needle nose pliers to pinch the bearing ends together for reassembly.

The 'boss' isn't a dry fit. I use white lithium grease on the boss (sparingly).

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So it was the 2 inch diameter metal material that is about 1/4" thick, which I now assume is called "the boss", that one needs to make the indents in. I did this and it worked great. No more lateral play. The point gaps are staying the same at all throttle positions. Hopefully this also fixes my mid throttle miss. I will let you know when I put the motor in the water.

Thanks Joe for the idea and thanks kbait for the additional charity on this procedure