engine won't shut off

G

gbb

Petty Officer 2nd Class
Joined
Aug 11, 2008
Messages
159
I have a 86 90 hp Johnson.In the past a couple time the engine would not stop when I turned the key to off. Started it today, it ran fine but everytime I tried to shut it off it keep running. I had to choke it to get it to stop. I got a manual, but I,m not much good at understanding the tests to perform. Can anyone give some advice on this, should I just replace the ignition switch?
 
SparkieBoat

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
Re: engine won't shut off

could be switch..you need to check your connections first..make sure all switch connections are tight..and check the ground wire where it connects to engine block after the big red plug under the motor cowl..loose/broken ground is usually the problem..could also be bad ground connection in big red plug..to test for a short..get a 10-15 foot piece of wire..connect to engine ground then connect to key switch ground and test..if problem persist..OHM test key switch..I cannot remember what color the power pack ground wire is but the black is ground and should have no resistance or very very little between black ground connection and the kill connection..
 
Joe Reeves

Joe Reeves

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Feb 24, 2002
Messages
13,262
Re: engine won't shut off

(Ignition Kill Circuit)
(J. Reeves)

A Black wire (ground) should lead from the powerhead to the powerpack. There will also be a Black/Yellow wire leading from the powerpack to a raised "M" terminal of the ignition switch. To complete the circuit, there will be a Black wire from the other "M" terminal of the ignition switch to ground.

When the key is in the OFF position = The two "M" terminals are connected,. effectively shorting/killing the ignition.

When the key in ON position = The two "M" terminals are not connected and the ignition is engaged.
 
milliesdad

milliesdad

Petty Officer 2nd Class
Joined
Dec 20, 2010
Messages
168
Re: engine won't shut off

Check the connections at the key switch, and the switch itself.

Please let us know what you find, as I have the same motor.
 
G

gbb

Petty Officer 2nd Class
Joined
Aug 11, 2008
Messages
159
Re: engine won't shut off

Thanks guys, It got so dang windy here, I won't be able to check it out till tomorrow. I will let you know how it goes.
 
Silvertip

Silvertip

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Joined
Sep 22, 2003
Messages
28,762
Re: engine won't shut off

Or you can simply disconnect the wires on the two "M" terminals and start the engine. Then connect the two wires. The engine should quit. If it does, the ignition switch is suspect. If it doesn't there is a wiring problem between the switch and the engine. But since the problem seems to be intermittent, repeat the test several times to be sure it is one or the other.
 
G

gbb

Petty Officer 2nd Class
Joined
Aug 11, 2008
Messages
159
Re: engine won't shut off

Looks like the switch is bad. Checked continuity between the m terminals and also checked to ground. The m(ground) was good but not the other M terminal. I am going to rig a kill switch for now, just order a new ignition switch.
 
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