no spark after tune up

[blackvelvetII]

Boat ran fine yesterday. I changed the plugs, cap, rotor and cleaned the very corroded ignition sensor. I also changed the fuel water seperator filter. I'm getting no spark no to #1plug.????1990 merc 7.4 (454) any help thanks.

 

[Don S]

Re: no spark after tune up

Go back over everything you did. Changing the cap, you may have killed the coil wire when removeing it. Did you get things back together right? Obviously not if it worked before.

 

[45Auto]

Re: no spark after tune up

Is it no spark to just #1 or no spark at all? If it's just #1, all it can be is cap/rotor, #1 wire, or plug.

If it's no spark to anything, my guess would be that when you

cleaned the very corroded ignition sensor

you damaged one of the very fine lead wires that go to it.

 

[180shabah]

Re: no spark after tune up

Back up and doublecheck everything - including the kill switch at the helm.

 

[blackvelvetII]

Re: no spark after tune up

Thanks for answering. I have no spark out to any plugs. My guess is a bad ignition sensor. I have dubble checked it and it appears that all the wires are intack. Any way to test?

 

[Showtime22]

Re: no spark after tune up

Get a light tester and check that there is voltage at the positive side of the coil when the key turns. If no voltage check fuses or rewire power from the back of the ignition switch.

 

[blackvelvetII]

Re: no spark after tune up

A light tester shows that I have power (12 volts) to both the + side and the - side of the coil when I turn the key on. I follow the wires, and the purple + side and the grey - side wire split and go to the switch on the Port side of the engine (riser). When I test that switch I have power at the point that the wires come in for both wires.

 

[snoski]

Re: no spark after tune up

Not being a smart ***; but did you remmeber to replace the rotor? I have also seen brand new rotors that were defective...