72 40hp johnson does not turn off

[lildoggy]

Hey Friends,<br />So far this board has helped me get new/old motor running. But when I turn the key to "off". It does not turn off. Is there a wire I'm overlooking? Can I manually shut her down in case of emergency. Sure would like to try the lake tommorrow.<br />Got the original manual for 72 40 hp Johnson. It doesn't help me with shut-off. Thanks in advance.<br />lildoggy

 

[fireman57]

Re: 72 40hp johnson does not turn off

probably have to choke it until it dies until you find the problem. Trace each wire. Make sure that all the ground wires are clean.

 

[lildoggy]

Re: 72 40hp johnson does not turn off

Thanks fireman, I do see that a wire to the vacuum cut-out switch is completely bare where the insulation has cracked off. Does this switch have anything to do with it? Also, the purple/white wire at the instrument cable plug is cut and not connected to anything. My wiring diagram shows this to go to the choke switch but it is wired and works, although with a different color wire.

 

[snagroms]

Re: 72 40hp johnson does not turn off

I just went thru an iginition switch replacement. 1st, Do you have a service manual? If not I would suggest getting one. The wiring diagrams in them are straight forwared and easy to follow.<br /><br />I would follow firemans advice on tracing all wires. I would add cleaning each end of each wire and check contiunity. Before you start disconnect your Battery to eliminate shorting something.<br /><br />The colors you described seem off but I don't have a manul for your motor so I'll pass along what I know. Purple w/white should be for the choke and go to terminal C on the ignition switch. All purple is for accessories usually powered on when the switch is turned on. For me this a Tach and overheat horn and goes to terminal A. I have a start in nuetral switch with a yellow w/red wire that actually starts and goes to terminal S. Red w/purple is the power and goes to terminal B. Black w/yellow is the stop circuit and goes to one of the M terminals. Usually the one that screws down into the switch versus one of the Metal tabs sticking up. Solid black is ground (or Earth for those not in the US) and connects to the M terminal that sticks up. The other end of the solid Black should go to ground. You may have two blacks one from the engine harness and one going to ground. Thats ok.<br /><br />Trace thru see were each wires starts, were they end, and make sure all are clean, in good repair and tight. <br /><br />Post back what you find.<br /><br />Hope this helps.

 

[rmpray]

Re: 72 40hp johnson does not turn off

I believe you have a magneto fired motor, which should mean your ignition switch actually shorts a coil to ground to shut down. Be sure the ground from the switch is good to the engine block, You should see an "M" on your switch, which goes via harness to one of the coils under the flywheel. Hope that helps. Oh, watch you oil mixture on this engine as they were designed around leaded gas, which was in itself a lubricant. <br />Good Luck<br />rob

 

[lildoggy]

Re: 72 40hp johnson does not turn off

Thanks for all the information. I did as Fireman said and used the choke as I turned the switch off and it killed the motor right away. It starts fine and runs good so far. Checked the wiring on my switch and as snagroms did, I think I better replace the switch. I do have the original service manual for this motor but its very general but does have an easy wiring diagram. The previous owner of this boat replaced the motor using the remote/wiring from the original. (Everything is sliced and diced.) I think it best to replace my switch and rerun the wiring as per the manual with exact color/gauge wiring. At least I will have confidence in everything and can learn what is where and what for. Its hard for me to see all the grounds under the dash area. Too bad this manual I have doesn't cover the remote control. Do any of them? Which manual could you suggest. I have the original, so another would be a good supplement just for added information. Thanks, I'm sure my task will lead to alot more questions and I appreciate your willingness to help. This board is fantastic - I'm having a hard time staying off of here and reading everything.

 

[rodbolt]

Re: 72 40hp johnson does not turn off

sliced and diced<br /> what color are the engine connector plugs? and what control box is being used? aslo what ing harness? by ign harness I am asking if its key in the dash, how many treminals are on the keyswitch the motor wiring is known, the control wiring needs a description.