magneto / coil plate -- binding

[perkdp]

I have a 1973 Evinrude, 18 HP (18304A) given to me in buckets. Got all back together and the magneto/coil plate is binding some and making it hard to turn the throttle handle. <br /><br />Is anyone out there familiar with this motor or problem? <br />Are there any ideas how to solve it? I'm afaid its going to twist off the throttle handle or bind wide open and run me over something.

 

[JB]

Re: magneto / coil plate -- binding

Check the coil to flywheel clearance, Perk.<br /><br />Each coil core should clear the flywheel by about .010".<br /><br />The stator could be binding on the crankcase lip that it rides on, also.<br /><br />Let us know what you find.

 

[Joe Reeves]

Re: magneto / coil plate -- binding

The aluminum ring that exists under the brass retainer should have the flat side facing up so that the underside flat portion of the brass retainer ring matchs up to it. Obviously having that aluminum ring upside down will cause binding.<br /><br />That being said. To obtain the proper coil clearance, this should help you.<br /><br />Have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit, creating the proper distance between the coils and the flywheel magnets. Faulty alignment creats friction and the yokes of the coils heat up, turn blue usually, and expand.

 

[Paul Moir]

Re: magneto / coil plate -- binding

In another post, perkdp says he has the engine running. So I don't think the flywheel is contacting the ignition coils. Unless he has no trouble throttling down. <br /><br />Some ignition coils are a little thinner than others, and so the screws that hold them down need to be a little shorter than others. It's worth trying loosening them off and seeing if that doesn't free up your armature plate. I think the phillips ones are the culprit, but I'm not sure.<br /><br />Do you have something to pull the flywheel with? You'll need a puller that acts on the three screw holes near the hub.

 

[perkdp]

Re: magneto / coil plate -- binding

Thanks guys. <br />I have a puller. <br />I have it running. <br />Same hard throttle both opening and closing. <br />Thing is,, it is / was hard before I put the flywheel on or hooked up the linkage. <br />Its almost like the crankcase end is a little big or the stator plate hole is a little small. <br />It will move both by hand and by throttle handle.<br />Just seems dangerous and causing alot of stress on all the throttle linkage. <br /><br />I'm considering removing it and doing a little fine sanding on it or maybe putting some vavle grinding compound in there and working the stator plate back n forth by hand. <br /><br />It sure don't seem right but I don't think it will require a replacement. <br /><br />I'll check the clearance that you guys gave just to be sure they're ok too.

 

[Paul Moir]

Re: magneto / coil plate -- binding

Usually the problem is that it's too loose, not too tight. Try to see if someone made a 'repair' on one of the brass bearings while you're in there.

 

[byacey]

Re: magneto / coil plate -- binding

I wouldn't put any abrasive of any kind there, likely you'll wear out the parts unecessarily without fixing the real problem. Find out for sure what's binding. check all the machine screws for the proper length. Perhaps you have some screws in the armature plate that don't belong, or are in the wrong holes. Loosen them off one by one until the plate turns freely.

 

[perkdp]

Re: magneto / coil plate -- binding

it could be that this coil plate is off of a different model or something. i got this motor from a friend who was given it by a friend cleaning his garage. found out it has been in buckets for about 4 years and don't know how long before that it was running. <br /><br />anyway,,, i'll look for repairs to the collar etc. <br /><br />during re-assembly, i put the coil plate down over the crankcase end without any of the other retainers etc. and it was really tight. i thought at that point it may have been because the crank-case wasn't fully aligned & torqued. <br /><br />there's not a "drag" adjusment on this thing somewhere that i'm overlooking is there ?<br /><br />paul, you mentioned brass bearings. do you mean the brass collar made/molded on the armature plate ?

 

[Paul Moir]

Re: magneto / coil plate -- binding

Yes, that's what I ment. Someone may have dented it up in a foolhardy attempt at tightening it. Usually it's the large brass hold-down bearing that's the real trouble. Denting up that one often helps quite a bit. <br /><br />The friction adjustment, if present, is always on the tiller arm I believe. So you can do away with it when you hook it up with remotes. I've never seen any sort of friction system for the armature plate.

 

[marinemech1]

Re: magneto / coil plate -- binding

try this:<br />remove flywheel<br />loosen the two phillips head screws that hold coils down a few turns<br />try throttle if its now free the screws are too long shorten or replace screws

 

[perkdp]

Re: magneto / coil plate -- binding

more info: <br />i removed the flywheel and armature plate , wiped all grease from the plate and crankcase lip, put the arature plate back on, turned the plate back and forth like throttling. Took the plate off again and noticed a couple of shiney spots on the crankcase lip and on the inside of the plat bushing indicating where it was rubbing hard. i gentley, a little at time buffed these shiney spots with 320grit sand paper (do little try again, do a little, try again) until thing work smooth. the plate now moves smoothly with throttle handle, and don't find any wobble in the plate. so i think this part is ok. <br /><br />now,,, i have idle trouble.... will start a new thread. Thanks...