Armature plate tight

I'm new to boat engines, been working on cars all my life. I bought a 1961 uniflite runabout with a 1956 30hp johnson (and 4 other similar engines in various stages of repair). It wasn't running right so I checked the points and found one had a hold down screw hole that was stripped. So....I replaced the armature plate - that was interesting. I cleaned everything along the way and regreased the plate bearing collar etc. When I put it together I found I couldn't rotate the plate unless the four attaching screws were very loose which does not seem to be correct. Any ideas?

Re: Armature plate tight

Once in awhile you will find a motor where somebody has deformed the brass retainer ring in an effort to tighten up a loose sloppy armature plate.

Re: Armature plate tight

Under the Armature plate, there is a brass retaining ring. Under this ring, there is a alumunum ring with one side beveled. This ring has to be installed with the bevel side facing down. If not, the armature will bind when you tighten the screw's.

Re: Armature plate tight

Thanks to everybody for the suggestions. This site is invaluable!!!

While reading other posts I saw that there is sometimes a shim between the armature plate and the aluminum ring to take up space when the aluminum ring is worn. I forgot to add (above) that I had to replace the aluminum ring since it also had a striped hole. The replacement ring must have been less worn than the one I removed. When I took out the shim and put it back together everything worked fine with no wobble or play.

When I started the engine (in a tub of water) it worked quite well. A little adjustment issues but they were OK for about 10 minutes until all of a sudden the engine quit and will not restart. It seems there is no spark. Put an inductive timing light on it but got no light. Held the wire close to the new plugs - no spark. Re-checked the points gap and armature placement - all OK. Wires all intact and out of the way of the flywheel with no abrading

The armatures had tested fine on my meter prior to assembly. There is a long wire that comes from the rear points to the bottom of the engine housing but is connected to nothing - it ran OK in this condition. I think it may be used to ground out the points to stop the engine - not sure though.

Any ideas?

Re: Armature plate tight

If you suddenly lost spark on both cylinders, you likely sheared the flywheel key. Pop the flywheel off and check.

If it did shear, file down any burrs on the crank and flywheel tapers, and lightly lap the two together with valve grinding compound. Don't overdo it, you just want a good contact pattern. Then clean the taper perfectly and torque the flywheel down with a new key (still available from the dealer) to 65 ft/lbs. You may want to go a little further.

Usually sheared flywheel keys are the result of either an undertorqued flywheel or burrs on the crankshaft/flywheel taper.

The wire should hook up to the vaccum cutout switch just above the carburetor on the port side (I think). You really have to have that hooked up as if you suddenly snap the throttle closed in neutral you can send the engine into run-away if it's not connected. You don't want to experience this as it's not good for the heart or the engine.

Re: Armature plate tight

Thanks Paul, that's exactly what is was. They're getting 6 bucks for those little guys. I'm pretty sure it sheared due to not being torqued correctly since I didn't have a way to hold the flywheel while applying torque. I just bought a Sears Strap wrench #9-45571 (boat shop suggestion) so I'll be able to torque it correctly. I did run it this evening and it ran great with the new woodruff key.

Thanks again for the info, I'll hook up the wire tomorrow.

Re: Armature plate tight

gcheris said:

Thanks Paul, that's exactly what is was. They're getting 6 bucks for those little guys. I'm pretty sure it sheared due to not being torqued correctly since I didn't have a way to hold the flywheel while applying torque. I just bought a Sears Strap wrench #9-45571 (boat shop suggestion) so I'll be able to torque it correctly. I did run it this evening and it ran great with the new woodruff key.

Thanks again for the info, I'll hook up the wire tomorrow.

Click to expand...

Re: Armature plate tight

I tried to hook up the wire but could find no where to hook it up. I took some photos of the engine but don'tknow how to put them in this message.

BTW- there is a second short (4") wire attached under the starboard side of the armature plate with no apparent place to go.

Lastly, when the ingnition is turned off, the engine does not stop. Will the correct placement of the wires allow it to stop?

Re: Armature plate tight

The old 30hp was normally set up to be stopped with either the choke switch or just throttled back. If you want though, you can run wires to stop it like more modern ones fairly easily. You just run a wire from each point, down through the armature plate, and ultimately to each "M" terminal on the keyswitch. You already have one wire coming down for the vacuum cutout so you really only have to run a wire to it and the other point.

The wire on the starboard side should hook up to the safety switch. Am I right? Is there one tucked up under the armature plate? If so, that wire runs to the base of the vacuum switch.

I don't have much information on the '56 so I'm guessing a bit here. Hopefully Boatbuoy will be by: he's a lot more familiar with that model.

Email the pics to me at paul.moir@gmail.com and I'll post them.