1984 Johnson 70 - No Spark

S

scrampbell

Petty Officer 2nd Class
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Starter engages, but no spark. Motor did something that didn't sound right at the exact moment that I turned the key off last (can't say for sure, but I think it originated from the key/ignition switch). Is there any chance a wiring problem in the console could be the culprit?

+ No spark at 1/2" gap in all three cylinders.
+ Known "iffy" wiring connections behind ignition switch at console.

Was there a safety lanyard on this motor? Would the starter still engage if there were a short in this jumper?

Thanks in advance.
 
tashasdaddy

tashasdaddy

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51,019
Re: 1984 Johnson 70 - No Spark

do you get spark at a smaller gap? check the kill wire, black with yellow chaser. could be shorted in the mess at the ignition, or else where. disconnect the wire, and try to start.
 
S

scrampbell

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Messages
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Re: 1984 Johnson 70 - No Spark

do you get spark at a smaller gap? check the kill wire, black with yellow chaser. could be shorted in the mess at the ignition, or else where. disconnect the wire, and try to start.
Click to expand...

+ No spark at 1/8" in all 3 cylinders.
+ Opened console and visually inspected wires... No visible new issues. Did not disconnect black/yellow wire and retest. It's routed to a plunger type kill switch that's been rigged to be inoperable. I'd like to rule out the power pack and related components before I start mucking with the wiring. (Major rewiring project slated for later this winter.)

I have a multimeter, is there a basic test to do at the engine to see if power is arriving at the engine that would normally translate into spark?
 
Gary H NC

Gary H NC

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Re: 1984 Johnson 70 - No Spark

unplug the wiring harness at the motor. Jump the starter over and test for spark.
If it has spark you know its a wiring or switch issue.
 
S

scrampbell

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Messages
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Re: 1984 Johnson 70 - No Spark

tashasdaddy said:
do you get spark at a smaller gap? check the kill wire, black with yellow chaser. could be shorted in the mess at the ignition, or else where. disconnect the wire, and try to start.
Click to expand...

+ Disconnected Black wire with green chaser at key switch and got spark.
+ Redid two very bad connections (hanging on by just a couple of threads type connections) at the key switch and did not resolve the issue.

So two questions...
? What next?
? Can I safely and normally operate the boat with this wire disconnected?

THANKS!
 
bktheking

bktheking

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5,057
Re: 1984 Johnson 70 - No Spark

You need to find out the problem, running boats with motors and disconnected wires - not good. Taking a stab that this is the wire that is connected to the "off" portion of the ignition switch. The directions Tashasdaddy sent you says either harness, ignition switch or shift switch, i'm taking a stab that you may need a new ignition switch to solve your problem. Frayed wires at the switch could have melted something internally in the switch causing a permanent ground situation, the switches are cheap- picked up my last one for twenty bucks.
 
S

scrampbell

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Messages
108
Re: 1984 Johnson 70 - No Spark

Got a new key switch today and will install it tonight. Can anyone help me match up wiring from the old switch to the new?

The old switch had these posts in order... S-C-A-M-B-M
(The 2nd M was the black/green wire that resolves the issue when disconnected.)

The new switch is labeled differently... S-C-B-M-I-M
Should the B from the old switch and the B from the new switch be the same or do you think that the ordering will be the same between the two switches (ie, old "B" matches new "I")?

Thanks again!
 
S

scrampbell

Petty Officer 2nd Class
Joined
Feb 25, 2009
Messages
108
Re: 1984 Johnson 70 - No Spark

RESOLUTION: Replaced the key switch last night and got positive results with my spark tester.

Thanks a lot everyone! Got my boat running again for just over $40, WAY less than taking it to a shop.

For more info about the key switch labeling question, see this post...
http://forums.iboats.com/showthread.php?p=2417007
 
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