1990 Mercury outboard 40HP no fire

[kruemdog]

Hello,

I'm hoping someone can assist me with electrical issues I'm having with my 40hp outboard ( 4cyl ). It cranks, but will not fire. I have pulled all 4 plugs and I see no spark. I have tested certain components with the meter and the only thing I can find wrong is that I'm not seeing any reading between the switch box and the coils. Could this mean that I need to replace the switch box. If so, does anyone know where I can purchase one that is fairly inexpensive. Please help. I don't really have a whole lot of money that's why I am writing into this forum.

Thanks

 

[jimlad]

Re: 1990 Mercury outboard 40HP no fire

Welcome to iboats kruemdog you could try dougrussell.com for parts

 

[Laddies]

Re: 1990 Mercury outboard 40HP no fire

If you have tested the stator and the trigger and they have passed a OHM it probably is the switch box. Presuming that you have disconnected the black/yellow kill wire from the box and cked for spark.

 

[kruemdog]

Re: 1990 Mercury outboard 40HP no fire

Thanks for responding. I disconnected the black/yellow wire and I still don't see any spark, so I'm assuming its the switch box thats the issue. I checked Ebay and I found a new one that is fairly inexpensive, but I don't know if its a good brand or not. It's a Mercury switch box made by Prufrex of Germany.

Mercury # 332-5772A7
Sierra # 18-5881

Thanks

 

[kruemdog]

Re: 1990 Mercury outboard 40HP no fire

I replaced the switch box with a new one and now I have fire, but the motor continues to crank and will not start. I took a look at each plug for spark and noticed that the spark appears to be weak. Could this weak spark be a issue with the ignition switch. Is there someway I can test this theory out?
Please help. I'm at a loss right now.