9.9/15 Front-to-back Armature Plate Movement

[JohnnyGuy]

Good afternoon all,

A couple of years ago I picked up a 1974 Evinrude 15hp E-Start that came with a 87 15hp parts motor. I have finally got around to fixing the '74 to be a runner again.
The '74 had issues with slop in the armature plate (up and down wobble) and the coils had some of their wires cut. I took the armature plate bearing (#44 in the parts breakdown photo attached) from the '87 parts motor. After I replaced the bearing it took out the up and down slop of the armature plate. But I noticed that the armature plate still moves ever so slightly every time the magnet passes the driver coil. If you watch the plate (#46) where it engages the neutral stop and you rotate the flywheel, the plate moves front to back (like you backed off of the throttle ever so slightly).
Anyone had this issue before? If so, what's the fix?
Thanks in advance.
JG

 

[racerone]

It is a strong magnet and yes you will see that on all of them.

 

[JohnnyGuy]

It is a strong magnet and yes you will see that on all of them.

Ok, I hadn't noticed it on any others I've worked on.
No fix/nothing to be worried about then?

 

[oldboat1]

Dunno. Doesn't sound right.

Might be an issue with the crankshaft bearing. Perhaps could install bearing from the donor motor. Check driver coil and stator placement(s), and make sure they are secure on the armature plate and that the armature support plate is secured.

 

[racerone]

Lot of work involved in changing the upper bearing !

 

[oldboat1]

^^agree. Might try to duplicate the movement by hand, starting with the flywheel (i.e., everything assembled). Then remove the flywheel and see if you can get any crankshaft movement -- repeat on down to (including) the armature support plate. If no movement of the crankshaft, work back up. Check the support plate on a flat surface (table saw top, perhaps) to make sure it is not warped. Move on up. When it's all reassembled and you've had your second beer, check the assembly of the stator and drive coil to make sure they are perfectly flush with the mounting posts and screwed down tight. Finally, check the flywheel for balance; look for cracks or chips (likewise for the magnets). If still no indication of problems, put the cover back on and go fishing.

 

[JohnnyGuy]

^^agree. Might try to duplicate the movement by hand, starting with the flywheel (i.e., everything assembled). Then remove the flywheel and see if you can get any crankshaft movement -- repeat on down to (including) the armature support plate. If no movement of the crankshaft, work back up. Check the support plate on a flat surface (table saw top, perhaps) to make sure it is not warped. Move on up. When it's all reassembled and you've had your second beer, check the assembly of the stator and drive coil to make sure they are perfectly flush with the mounting posts and screwed down tight. Finally, check the flywheel for balance; look for cracks or chips (likewise for the magnets). If still no indication of problems, put the cover back on and go fishing.

Excellent breakdown. I'll check it out and report back.
Many thanks!

 

[kbait]

Lateral play in arnature plate will change point gap when it moves, changing timing on points opening when spark occurs. I fix by pulling armatureplate and modifying the boss it ‘rides’ or pivots on. Use a center punch/hammer and lightly punch the sides of boss at 12-3-6-and 9 o’clock. This will effectively increase the bosses diameter by leaving 4 small waves of metal at punch sites. Dry fit armature plate and check lateral play. Should be better.. now punch the same 4 holes again and test fit.. eventually, all play will be gone, and slight resistance in plate pivoting. This is where you want it. Add a dab of grease to your punch marks, reassemble, set points and go fish!
This fix works long term. Good luck!

 

[flyingscott]

That stator has nothing to do with the upper bearing it does not even touch it. Unless the flywheel itself is moving up/down or side to side your bearing is fine. Your problem is you have a 1974 9.9/15. Those stators were crappy from the get go, there were update kits that replaced most of the stator assembly. They just were not machined very well. I usually convert them to the newer cdi setup and they make decent little motors. Kbait idea of staking it is good but with those motors it ends up being temporary.

 

[JohnnyGuy]

Lateral play in arnature plate will change point gap when it moves, changing timing on points opening when spark occurs. I fix by pulling armatureplate and modifying the boss it ‘rides’ or pivots on. Use a center punch/hammer and lightly punch the sides of boss at 12-3-6-and 9 o’clock. This will effectively increase the bosses diameter by leaving 4 small waves of metal at punch sites. Dry fit armature plate and check lateral play. Should be better.. now punch the same 4 holes again and test fit.. eventually, all play will be gone, and slight resistance in plate pivoting. This is where you want it. Add a dab of grease to your punch marks, reassemble, set points and go fish!
This fix works long term. Good luck!

This is my concern (changing timing). When you are referring to boss are you referring to part 29 in the breakdown attached to my first post?

 

[kbait]

No. The armature plate (#1) pivots on the boss on top of powerhead. It it surrounds the top of crankshaft..

 

[JohnnyGuy]

No. The armature plate (#1) pivots on the boss on top of powerhead. It it surrounds the top of crankshaft..

You are talking about what I have shown with a red arrow. Correct?

When I removed the armature plate I noticed the the brown Delrin bearing moves back and for on this I'm assuming this is where the play is coming from.

 

[kbait]

No.. it’s where the center hole in armature plate contacts boss..

 

[JohnnyGuy]

No.. it’s where the center hole in armature plate contacts boss..

OK pretty certain I understand now.
Punching the vertical surface that the red arrow is pointing to.

 

[kbait]

Yep

 

[JohnnyGuy]

Thanks guys.
I punched the boss as recommended by kbait and it took out the play with the armature plate.
I do have a misfire when I throttle down from the neutral stop, which causes it to want to stall.
Wire from the driver coil to the top coil was spliced with a butt connector, I'm going to heat shrink and solder it, see if that fixes the problem.

 

[RBoyd1971]

I have this exact same motor and it has the same play you mention in the armature plate. However, it hasn't affected it's running in the least. I can crank it once it's warmed up by just spinning the flywheel with my hands, no joke. Been an awesome motor. I set the points with my DVM. Be sure the condensers are good.