'75 15hp stator plate wobble

[kbait]

Electric start motor w/charging stator. I tried using a punch to 4 spots around the motor boss and it worked briefly, then sloppy again. I've resorted to opening the points a bit for the lower cylinder and moving the charging coils back behind the normal placement just a bit to keep it from rubbing on the flywheel. It idles like a dream, but not quite right at high speed (I'm sure that's do to the variable point setting due to the wobble). I also tried to add some .005 brass sheet stock, cut into a strip, but I not enough clearance to re-install. I've used the punch trick on 9.9/15's w/o charging coils with great results, but the extra magnets on this motor REALLY want to jerk the plate around, and nullify (quite quickly) that quick-fix. I've also heard that the '74 -'76 (I believe) had a recall for that particular problem, but whatever the fix is, it's not available any longer. Could a new (used) stator plate fix the problem? I have also tried 'punching' the brass ring that is in the plate, to the same result. Love the motor, but would just love to have that slop gone, as it obviously plays havoc on point settings! Thanks in advance..

 

[bktheking]

Re: '75 15hp stator plate wobble

This was the part # to the fix in this thread

http://forums.iboats.com/showthread.php?t=111097

Is this what you tried?

--------------------------------------------------------------------------------

(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.

Use a small amount of anti corrosive grease between the aluminum ring and the brass support plate and also on the brass bushing of the armature plate when all is well.

 

[R.Johnson]

Re: '75 15hp stator plate wobble

That mag plate does not pivot on the upper crankcase bearing support, or boss'es like the older engine's. I doubt if trying to peen the brass bearing ring would have much effect. There was a mag plate update kit available to solve this problem. I don't know if it is still available.

 

[bktheking]

Re: '75 15hp stator plate wobble

They ride on a plastic bearing don't they and have a support plate. I don't understand the punch trick at all. On my motor (83 9.9) the armature plate has a bearing in which the plate sits on, the plate is screwed into the power head while another plate with a throttle arm site underneath. The stator/armature plate fits tight over the powerhead so there is no room for wobble. Was the 74-76 a different total design as I thought the powerheads were alike.

 

[bktheking]

Re: '75 15hp stator plate wobble

Looking at the design from a 75, they are almost the same, where is the wobble in this case?

 

[R.Johnson]

Re: '75 15hp stator plate wobble

bktheking: That's how it work's. It's been so long since I've done one of those kit's, I don't remember just where the wobble come's from.

 

[kbait]

Re: '75 15hp stator plate wobble

Thanks for that link, bktheking. Sounds like any replacement mag plate that I'll find will be the 'faulty' kind, and I cannot use a '77 or newer, as they went to CD ignition. I did replace the plastic support ring with no noticeable effect.. After fall fishing, I'll figure out a way to build up the aluminum boss on the powerhead to more closely mate to the brass ring in the mag plate to eliminate, or at least minimize the slop. Any other ideas are more than welcome!

 

[bktheking]

Re: '75 15hp stator plate wobble

So is it the powerhead that is worn or the mag plate?

 

[kbait]

Re: '75 15hp stator plate wobble

It's one or both. The brass ring that is fused to the aluminum mag plate cannot be removed/replaced, and that actually doesn't appear to be worn, the aluminum 'boss' on the powerhead is likely worn some, and it apparently doesn't take much to cause alot of slop. And the extra flywheel magnets and charging coil attraction doesn't help, as the stator plate is tugged toward the magnet very strongly as the flywheel spins. Much, much more than a non-charging coil motor ever would. The design is very adequate for a standard engine, but lacking for an e-start model w/charging coils. I imagine I could get a standard mag plate w/o charging coil w/standard flywheel and eliminate the problem, but I'd also lose the charging capabilities of the motor. Perhaps I'd only need to remove the charging coils to get the same effect, and the plate wouldn't get yanked around so much, and 'peening' the boss in 4 spots to remove the slop would likely work long term, as the plate wouldn't be jerked around to quickly nullify the effort. I hadn't thought of that possibility..

 

[kbait]

Re: '75 15hp stator plate wobble

Success! Removed charging coil and re-peened the block boss, and no wobble after testing. Thanks!

 

[F_R]

Re: '75 15hp stator plate wobble

Success! Removed charging coil and re-peened the block boss, and no wobble after testing. Thanks!

Good luck on the fix. As you know by now, they wobbled excessivly when new. There were several factory fixes under warranty, none of which worked well. OMC lost a ton of customers over this one.

 

[kbait]

Re: '75 15hp stator plate wobble

Lake tested this morning. Idles so slow I have to speed up to troll, and I got 4 walleyes!
Here's a link to pic's that might work:
http://www.facebook.com/home.php#/album.php?aid=8039&id=100000176372574

 

[bktheking]

Re: '75 15hp stator plate wobble

Nice catch, those are huge! Must a been the 15hp fix that brought you luck!

 

[jay mendoza]

Re: '75 15hp stator plate wobble

I have a 1975 9.9/15 manual rope start. Just replaced the power head with a new one, stator plate was a bit sloppy, so it appears the wear occurs in the plate and not the power head flywheel bearing boss.

 

[kbait]

Re: '75 15hp stator plate wobble

Thanks for the info!