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74 mercury 115hp 6cyl problems

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bigfoot246

New member
hey guys, just bought my first boat trying to get a handle on everything i have. its a 74 kona with a 115hp mercury straight 6. i have yet to run the engine due to a electrical issue an ignition problem. first problem is not being able to turn the key my guess is the contacts may be gummed up? not sure....is there a some sort of ignition lock im not aware of? next i noticed im not getting batt. power on the engine main harness. is this because i cannot turn ignition to "on" or some fuse or something. any help with this would be awesome, also if anyone know where to get a wiring diagram that would also be helpful. thanks.​
 
Don't laugh, but are you sure that's the right key? There is NO ignition key interlock. With the ignition ON, there will be power coming from the motor for the choke and starter circuits.

Jeff
 
yea ill have to make sure i have the right key, it goes in but just doesn't turn...any way to bypass the switch for now....i took the "MerControl" apart to probe some wires on the switch an still have to power, wouldnt there have to be constant 12v to the ignition?
 
There HAS to be 12 volts there for starting and the choke, key off or on. If you can, remove the controls and take it to a Merc dealer. They will try a bunch of keys and, hopefully, one will work. There's not many combinations of them--it's not like cars.

Jeff
 
so after the repair of a broken wire i got 12v to the ignition switch, i also ordered a new switch with key. in the mean time i bypassed the switch just to see how the engine would run, an another problem occurred, it seems to crank around fine but with choke on an fuel primed it would not fire, what im curious with is how to diagnose spark an fuel properly on these, thanks for the help.
 
The kill cicuit may still be working. Check her for spark and, if there isn't any, look for an orange or black/ yellow wire coming from the spark box and disconnect it.

Jeff
 
good point, ill check her out for that wire,cause im not getting spark. an as far fuel, i have an electric primer from the tank, an i'll hold the button for about 3 to 4 seconds but dont see any fuel getting to the lines on the carb. i do notice a minor leak i believe coming from some linkage starting at the top carb.....this linkage goes to each carb, i think its the throttle link...????...anyone know if this could be a o-ring from the carb to the link or some common prob? any advice would help. thanks!

........i believe this is a triple carb setup.....
 
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