Category Archives: Ignition Switch

Has Power. Won’t Start.


I have a 2004 Premier pontoon boat that will not start.

Premier Pontoon Boat

I have battery power as the motor will raise and lower, the radio will come on, etc.; however, the engine will not crank.

It worked well prior to putting it away for the winter.

What can I trouble shoot? Is there a fuse? How can I tell if the ignition switch is bad? Is there a neutral switch that can go bad? When I turn the key, nothing happens. BTW, I have a 50 horse Four Stroke Mercury.

Thanks in advance for any advice.


First check the in-line fuse on the engine near the starter solenoid (follow the battery cable into the engine from the battery to the starter solenoid). If the fuse is good, check for power at the key on the red or red/green wire.

This will solve your problem,


Kill Switch Culprit?

Hi Kevin,

My friend has a 24 ft Lowe pontoon boat with a 50 hp Johnson motor – and he wanted me to ask you a question.

One day he took it to the lake and started right up, ran it all day without any problems. That night, at home, it wouldn’t start. He tried again the next day, it started, moved it around didn’t start, did it again it started. Boat wiring safety stop switch

He is wondering where to begin or what to look for. He believes that it probably a simple problem but doesn’t know much about marine electrical. We really enjoy your site and thought that you might know where to start to solve the problem.



Hi Pam,

I would check the emergency shut off switch (the safety lanyard).

If it is faulty, the engine will turn over, but there will be no spark. There is a similar circuit in the key switch. Both will cause the symptoms that you are describing.

Hope this helps,


Ignition Cognition

Hello Kevin,

I have 1970’s Mercury 20hp on my pontoon boat. I have to replace the ignition switch.

My new ignition switch has five terminals, A M B M and S. My wires colors are red, black, yellow, orange, gray and tan. I also have a push button, which I believe is a choke.1970 Mercury outboard engine ad

On the original switch, the gray ran thru the choke and the tan ran thru the switch and the choke button.

Can you please tell me what goes to what?

Sorry if I haven’t explained this well, but I am lost when it comes to marine wiring.

Thanks for the help.


Hi Alex,

These are not standard boat wiring colors. You will need to do some wire tracing to determine what is what.

For the switch

  • A – Accessory – feeds power to gauges – choke button – etc
  • M – Magneto – one of two wires required to shut down engine
  • M – Magneto – the other wire required to shut down engine
  • B – Battery – Constant 12v power
  • S – Starter

One of the magneto wires will actually be a ground wire connected to the engine block or negative bus. The second wire will connect under the flywheel of the engine.

The starter will run through the neutral safety switch in the engine control and then to the starter solenoid in the engine.

The battery wire will get it’s power from the positive battery cable connection post on the starter solenoid.

The choke wire will be connected to an electric choke solenoid mounted near the carburetor.

Hope this helps,


Inline Ignition Fuse

Hi Kevin,

I need a little marine electrical help.

I have a 2006 18′ Manitou Aurora pontoon boat and I installed a depth sounder over the weekend. Manitou Aurora Pontoon Boat

While I was searching for a positive feed with my light tester I touched a connection behind one of my other gauges. I got spark and now I have no ignition power. I still have power to my radio and lights but not to my gauges or ignition.

Any ideas?

I’m hoping it’s just a fuse but as you can see I’m not that bright when it comes to marine wiring.

Thanks in advance.


Hi Dan,

On Manitou boat wiring, there is an inline fuse under the engine hood that supplies power to the ignition switch. This fuse is usually within a couple inches of the starter solenoid and the main battery cable connection.

This will solve your problem,


Purple Power

Hi Kevin,

My name is Brad and I was given your email address by a friend. He said I could email you with a marine electrical question I had for my parents’ pontoon boat. Any and all help would be greatly appreciated. Faria Tachometer

My parents have a 2006 18′ Suncruiser with a four-stroke Mercury 25hp outboard. The tach, fuel gauge, and volt gauge stopped working and I can’t seem to figure out the problem.

I was thinking that the problem could e a common ground wire since all three gauges went out at once, but I tried a different ground and couldn’t get anything to work.

I also checked the two 20 amp fuses under the motor cover and they were both good. I don’t know if either of those were for the gauges, but I see no fuse panel anywhere on the boat.

Thank you for reading my email, and also for any insight you may be able to provide.


Hi Brad,

If all of the gauges have quit, it is either the ground or the power. Since you have already checked the ground, I would chase down the power lead.

According to standard boat wiring colors, you are looking for a purple wire that runs from the ignition switch up to the gauges. If the boat starts, then you have power to the switch. Trace it from the key to the gauges to find your problem.

Good luck,


Gauge Power


I am going to overhaul the boat wiring on an old Sun Cruiser pontoon.

It will have the following accesories:

  • Livewell pump
  • CD Player
  • Navigation lights
  • Stern light
  • Boat Horn

Here’s me question:

The power for the gauges…I have no purple wire or pigtail to go to the positive boat bus bar to power the gauges. Would I have to tap into the tach from the three pin connection from the controls to make this happen? Maybe the three female pins below keyswitch on the control? Is this okay?Speedometer

I have a cable that goes it to it with black, grey and purple boat wiring. Or can I just use go from the three pin connection from the controls the purple wire to the positve bus bar to tach, volt, and fuel gauge

My setup is as follows:

  • 1989 Evinrude 110 hp with power/tilt trim
  • OMC side mount controls with tach plug below key switch
  • Tach gauge
  • Volt gauge
  • Fuel gauge
  • Five Switch Marine Electrical Panel
  • Fuse panel
  • Ground bus bar
  • Positive bus bar
  • Battery switch
  • Two batteries starting/deep cycle for accessories



Hi Eddie,

You can certainly connect to any purple at or near the ignition switch/control to power up your gauges. In that era, OMC only used purple for switched ignition power. Purple/White was for the choke.

Hope this helps,



Can I also use the black ground wire from the tach harness to ground all of my gauges?Fuel,Tach,Volt or should these be grounded somewhere else.


Yes you can.


Light Show!


I have a 2003 Premier Pontoon. It has a marine electrical switch panel that includes a stereo off and on.

When any of the lights are on, a red light is on for that particular switch.

The issue is sometimes when I turn one on, all the lights on the panel start randomly flashing, then after a few minutes it stops and only the one I turned on stays on.

Thanks for your help in solving this boat wiring mystery.


Searching for the answer

Hi David.

It sounds like the lights on the switches in your panel share a common ground with stereo.

Make sure all connects are tight and corrosion free. If the problem continues, I would run a new ground wire from the switch panel to your battery negative.

Hope this helps,


Purple Popping

Hi Kevin,

I just rebuilt the motor in on my old Suncruiser pontoon and need your help with some of the boat wiring.

Coming out of the ignition is a purple wire. Well, if I leave it hooked to the ignition, it gets real hot and keeps popping fuses. It seems to go to the positive side of the coil.Ignition Switch

Any ideas?


Hi Carl,

Disconnect the wire from the coil, if it still pops the fuse, there is a short in the wire between the ignition and the coil. If it stops, replace the coil.

Keep in mind that the purple ignition wire also provides power to your instrumentation.

Hope this helps,