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1988 Mariner 20

N

nytebyte

Regular Contributor
Went to fire up my sons 1988 mariner 20 and its no go. Tested for spark and didnt have any at either cylinder. Disconected the kill switch-both on the tiller and the safety cord and still no spark. Any idea of where to go next? I wouldn't think both coils would go at once? Switch box or trigger? Any help on how to test them would be great! Thanks, Jim
 
You can try some ohm tests on the stator and the trigger to see if they are the culprit.

If you have an ohm meter you can test the stator leads:

The stator leads (to the switch box) are black/white stripe and black/yellow stripe.

With the ohm meter set to X1 test the black/white to a good ground point - should be 120-180 ohms

With ohm meter set to X100 test the black/yellow to a good ground point - should be 32-38 ohms

With ohm meter set to X100 test between the two stator leads (blk/wht and blk/yel) - should be 31-37 ohms.

(readings can be out a "bit" but "significant" resistance or complete resistance would indicate bad windings)

Then the Trigger:

The trigger wires to the switch box are brown and brown with a yellow stripe.

Set the ohm meter to X100 - test between the two trigger wires (brown and brown/yellow) - should be 6.5-8.6 ohms - again, a very little wiggle room.

If both of those test "ok" then the switchbox is the likely culprit BUT do make sure that the switchbox has a good ground. In the (timeframe) of that model it probably has a black ground wire from the switchbox that goes to one of the switchbox mounting screws (usually between the switchbox and the block on a ring terminal "pinned in place" when the screw is inserted.

The resistance tests are "mostly" a reliable test but they can also be tested for correct voltage with a DVA tester or a DVA adapter and a regular multi-meter as a "last test" for calling it the switch box (which is proven bad by proving everything else is good)...
 
Thanks. We will get on it and let you know. It was fine last fall and went to start it now that the ice is off the lakes and this happened.
 
I was told that just disconnecting the kill switch wont eliminate that as the problem and that it should be jumped? If so how is that done? He thought that the kill switch was the problem but didnt know how to jump it. Thanks, Jim
 
The kill switch(es) - one on the cowl and the other in the tiller handle if equipped are joined together and connect via a single bullet connector at the (front) of the switchbox.

Just follow one of the black/yellow stripe wires to that connector and disconnect it right at the switchbox - that will take them totally out of the equation.

Of course, if the motor does start you will have to choke it out or (kill it) some other way - run it out of gas etc to stop it.
 
Thats what I had done so it sounds like we are back to the switchbox! I think my sons guy thought that the kill switch was live until it was hit and that isn't the case.
 
No the kill (circuit) is basically just a ground.

Power from the switchbox is looking for the easiest path to ground and it's easier to go right to ground then jump the gap on a sparkplug. So when you switch to "kill" it completes the circuit and suck up (enough) of the power that it won't fire the plugs.
 
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