1958 JohnRude 35 RD21/Lark

I have a 1958 Johnson RD-21 , and a 1958 Evinrude 35 Lark, Same engine except for their cowls near as I can tell. Anyway the flywheel armature plate from the Johnson fits on the Evinrude (trying to get one running). There are four screws (two short through the armature plate and two long, one thru each coil heel that the Clymer B734 manual refer to as Take down screws - armature plate. If I take them down they lock the armature down keeping it from moving (which probably explains why the engine wouldn't start). What are these screws used for and should they be removed when not in use?

Re: 1958 JohnRude 35 RD21/Lark

No...they're needed. The engine can't run without them. I'm trying to figure out what's missing there under the armature plate that's causing it to bind up, but can't think of what it might be, unless you somehow got the plate turned upside down then reassembled things that way....

Re: 1958 JohnRude 35 RD21/Lark

It's possible that the screws are not original, in which case they may be too long and are bottoming out under the retainer ring. The original screws have threads only along the bottom 1/2-inch or so with the rest of the shank being smooth. This allows the screw to come out of the retainer ring without coming out of the coil.<br /><br />Aluminum retainer ring should be assembled flat side UP, tapered side DOWN. A light coating of grease on the inner rim of the brass retainer ring will help things slide around.<br /><br />- Scott

Re: 1958 JohnRude 35 RD21/Lark

Originally posted by Chinewalker:<br /> It's possible that the screws are not original, in which case they may be too long and are bottoming out under the retainer ring. The original screws have threads only along the bottom 1/2-inch or so with the rest of the shank being smooth. This allows the screw to come out of the retainer ring without coming out of the coil.<br /><br />Aluminum retainer ring should be assembled flat side UP, tapered side DOWN. A light coating of grease on the inner rim of the brass retainer ring will help things slide around.<br /><br />- Scott

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Re: 1958 JohnRude 35 RD21/Lark

Gents, thank you both for your quick replies. The screws from both armature plates are the same length, so I don't think they are bottoming out. The longer screws (through the coils) match Scotts description, the shorter ones have retainers on the bottom side. I guess I don't understand the function of the retainer ring. Is it supposed to rotate? Is it connected to anything inside the case? The drawings I have in the Clymer pub are not very clear and do not include an exploded view of the the retaining ring area. The retaining ring does appear to be installed correctly as it has four threaded holes into which the screws screw. If it needs to be lubed how does it come out?

Re: 1958 JohnRude 35 RD21/Lark

The retainging ring is held down by the plate that has 4 screws that mount to the block . lube retaining ring so it slids under holddown plate easy. when the tining plate is mounted down you only use 2 bolts .

Re: 1958 JohnRude 35 RD21/Lark

Gents: I think I figured out the problem. I took the armature plate of and figure out how the retaiing ring works, took it off, cleaned and lubed it. Put it back together again and it still binds. Compared screws with spare unit screws and discovered I missed the washers between the armature plate and the screws. I haven't tried it yet (its too dark) but i suspect that the extra thickness of the washters will make the difference between binding and not binding. Will try tomorrow in the light. Thanks ever so much for your help.

Re: 1958 JohnRude 35 RD21/Lark

Hey strouds, <br /><br />There are four screws to hold the timing plate down, not two. <br />If you only use two, you are asking for trouble.<br /><br />Brother Acht, You have probably hit the nail on the head, so to speak, with the washers, If the screws go down to far they will hit hte block and bind it up. <br /><br />Also check the alighnment of the coils, to make sure that they won't hit the flywheel. The edges of the coil laminations should be flush with casting of the timing plate, where they are bolted down.<br /><br />Also be sure that when all is finished and you put the flywheel back on, that you torque it down correctly, or you will end up with a sheared off flywheel key.