1963 40 hp johnson

[gypsy121761]

Can any body help me? My 40 hp johnson outboard runs great for a while on plane, then acts like it runs on 1 cylinder, shut it down for a few min then runs great for a bit then the same thing? There's one wire thant comes from the armature plat that don't know where it plugs into and I'm almost sure that's the problem but dont know where it goes. One plugs into the side cut out switch but the other dont know?? Any body help me?? Much appreciated, thank you Jess

 

[Daviet]

Re: 1963 40 hp johnson

Is it a black wire coming from the mag plate, if so it is a kill wire for a set of points, insulate it so it can't short out on anything.
You need to check spark when it happens and see if you are loosing spark to a cylinder. Sometimes a coil will overheat and shut down until it cools off, if thats the case you need to pull the flywheel and check the ign system.

 

[gypsy121761]

Re: 1963 40 hp johnson

Is it a black wire coming from the mag plate, if so it is a kill wire for a set of points, insulate it so it can't short out on anything.
You need to check spark when it happens and see if you are loosing spark to a cylinder. Sometimes a coil will overheat and shut down until it cools off, if thats the case you need to pull the flywheel and check the ign system.

yes it's a black wire but not as thick as the other wire from the mag. It is hot wire but dont know where it goes? If i put it where the other one is on the side switch it will spark Im pretty sure it dont go there..

 

[Daviet]

Re: 1963 40 hp johnson

Maybe this will help you out, don't worry if you don't have electric shift, the ign wiring is the same.
I can't think of any wires coming from the mag plate that has voltage on it. The black wires from the mag plate are used to short out the ign system to kill the engine. The black wires might spark when you ground them because you are shorting out the ign system.
http://www.maxrules.com/graphics/omc/wiring/61_66_40HP.jpg

 

[gypsy121761]

Re: 1963 40 hp johnson

The two wires from the coils come out of the plate one is going to the cut out switch and the other nowhere?

 

[lindy46]

Re: 1963 40 hp johnson

The second wire goes directly to the key switch through the wiring harness. Has it been cut off, or is there a connector on it? If it has a connector, look for another black wire going to the plug connector on the starboard side of the motor, where the wiring harness plugs into. That wire should not be "hot".

 

[gypsy121761]

Re: 1963 40 hp johnson

The second wire goes directly to the key switch through the wiring harness. Has it been cut off, or is there a connector on it? If it has a connector, look for another black wire going to the plug connector on the starboard side of the motor, where the wiring harness plugs into. That wire should not be "hot".

Wire has been cut no conector... wire is hot tho? Any ideas? Thanks, Jess

 

[lindy46]

Re: 1963 40 hp johnson

Loose wire coming from under the armature plate should not be "hot" You need to confirm where that wire comes from. May have to pull the flywheel to see what's going on.

 

[gypsy121761]

Re: 1963 40 hp johnson

If I conect that wire to the key switch do you think that might cure my problem, and where in the key switch would it go? That is the only wire that is'nt connected to anything. My boat is a 10.5 ft marlin runabout, I can haul *** about 50 mph for around 5 min then slow it down to an idle and then take off again ,and wont even plane, what you think? Thanks, Jess

 

[lindy46]

Re: 1963 40 hp johnson

The kill wires connect to the "M" terminals on the keyswitch. If you have a loose kill wire, it could be shorting out and causing you to lose 1 cylinder. But I'm thinking you probably have a bad coil which is misfiring when it heats up causing you to lose a cylinder.

 

[gypsy121761]

Re: 1963 40 hp johnson

The kill wires connect to the "M" terminals on the keyswitch. If you have a loose kill wire, it could be shorting out and causing you to lose 1 cylinder. But I'm thinking you probably have a bad coil which is misfiring when it heats up causing you to lose a cylinder.

Could be a coil but really don't think so because they both are brand new..but I'll check them thanks you, Jess

 

[gypsy121761]

Re: 1963 40 hp johnson

wire is only hot when it's running? When not running it's not hot..What ya' think?

 

[gypsy121761]

Re: 1963 40 hp johnson

need to know where both wires from under the armature plate go? Can anybody help me out?