# Mercury 20hp no spark



## Morgan_Duett

I have a 2000 mercury 20hp 2 stroke it has compression it has fuel but no spark, it ran with a sluggish (sounded like one cylinder was firing) so I replaced the plugs and one plug wire was broken so I put a new wire on too and it ran like a scalded dog for about 1 hr went back to the boat ramp and had my buddy get the trailer and it stalled about 4 times but kept turning back on. Got back to the house and it turned on and cut off before I could wash it out now there's no spark at all?


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## HaMm3r

Well, if you have no spark in either cylinder my guess would be stator, assuming there's no short to ground somewhere. Could be several other things, but in my experience the stator fails more often than just about anything else.

Here's some easy tests you can do to help diagnose the issue. I didn't write them. They were copied from someplace on the interweb long ago...



> Remove the black/yellow wire from the switchbox(powerpack) that runs from the kill switch. This will eliminate the kill switches totally. If it fires then you will need to find out where the kill switch circuit is grounded. If that does not work, the next thing to check is the stator which is under the flywheel. It can be checked with a ohm meter. Remove the black/yellow wire that runs from under the flywheel to the switchbox and the black/white wire that runs from under the flywheel to the switchbox. Between the black/white and the engine ground the reading should be between 120 to 180 ohms. Between the black yellow and engine ground the reading should be 3200 to 3800 ohms. Between the black/yellow and the black/white should be 3100 to 3700 ohms. If it is anything other than that, the stator is bad. If the stator reads good, then you need to test the trigger coil which is also located under the flywheel. Remove the brown and the brown/yellow wire from the switchbox. Between the brown and the yellow/brown should be 650 to 850 ohms. Any other reading means the trigger is bad. That pretty much checks out your whole ignition system. If the kill switch system is OK, I would guess that the stator is bad. I hope this helps.
> 
> 
> 1996 to Current Models
> 
> Try disconnecting the black/yellow wire from the engine to check the kill circuit first. If the engine still does not start, change the white/green and the green/white stator wire. This will change the engine starting cylinder. If the problem persists in the new cylinder, the stator is bad and needs to be changed.


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## Morgan_Duett

Thanks ham I'll do some tests tomorrow!


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## Creek Runner

Those instructions only test the resistance, you will need a DVA to test the charge coil outputs on the stator/trigger. Also if it is an eletric start disconnect the regulator/rectifier and see if you have spark.


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## Morgan_Duett

It is electric start I'll try that too


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## HaMm3r

You want to listen to Creek, he knows his chit. 

Most of us don't have a DVA though, so I have successfully diagnosed bad stators many times using those instructions. Doesn't mean it'll work in every case, but I've not ever had a misdiagnosis thus far.

Be sure to let us know what you find out.


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## RTS

> You want to listen to Creek, he knows his chit.
> 
> Most of us don't have a DVA though, so I have successfully diagnosed bad stators many times using those instructions. Doesn't mean it'll work in every case, but I've not ever had a misdiagnosis thus far.
> 
> Be sure to let us know what you find out.


Yeah but check the obvious first.

Check your kill switch especially if you added a tiller extension. Go ahead, ask me how I know [smiley=frustrate2.gif] [smiley=frustrate2.gif]


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## HaMm3r

> You want to listen to Creek, he knows his chit.
> 
> Most of us don't have a DVA though, so I have successfully diagnosed bad stators many times using those instructions. Doesn't mean it'll work in every case, but I've not ever had a misdiagnosis thus far.
> 
> Be sure to let us know what you find out.
> 
> 
> 
> Yeah but check the obvious first.
> 
> Check your kill switch especially if you added a tiller extension. Go ahead, ask me how I know [smiley=frustrate2.gif] [smiley=frustrate2.gif]
Click to expand...

Lol...that is the very first step in the instructions, btw.


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## Morgan_Duett

The stator was bad


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## HaMm3r

> The stator was bad


Glad you found out what it was.  At least it's an easy fix and not too terribly expensive to replace.


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