Ignition Key Not Working (Won’t crank using ignition switch)

[estecks]

Firstly, I got a 1998 Bayliner Capri 3.0L with a lot of electrical issues and some wires even cut (bilge pump and blower so far that I found.) When I jump the starter manually, I get spark and the engine cranks over. But when I try turning the ignition switch, nothing happens, except power going to the gauges.

What possibilities would cause the ignition switch not to start the engine? I do have the safety switch ON, near the throttle control. The purple wire 12+ from the ignition switch would go to the fuse box, correct? I know the yellow and red runs to the starter solenoid.

Please help me diagnose the problem. I'm guessing a wiring problem.

[dktool]

Dead man switch and or neutral safety switch.
Start there.

[Nauti_Mike]

Are you getting power to the slave solenoid that’s mounted on the engine? Do you have the wiring diagram for your engine?

[builderdude]

I’ll guess a faulty slave solenoid. Check for positive DC voltage at the small terminal with yellow/red wire attached while the key is in start position. Jiggle the shifter to ensure the neutral safety switch is closed. The kill switch is unrelated as it doesn’t impact cranking.

[estecks]

I'll check all of those tomorrow. Thanks! I did replace the slave solenoid last week as well as the starter, spark plugs and wires, distributor cap and ignition coil.

[estecks]

Dead man switch and or neutral safety switch.
Start there.

How do you test the neutral safety switch?

[2850Bounty]

The neutral safety switch interrupts the S circuit. (S = solenoid)
It closes when in Neutral (allowing for starter motor action) , and opens when NOT in Neutral (preventing starter motor action)

The S circuit is typically a yellow wire with a red stripe.

[simo]

I'm sure you already checked that your throttle lever is fully engaged in the neutral position. Once in a blue moon I had to "jiggle" mine in the neutral position to get the ignition switch to work.

[2850Bounty]

I'm sure you already checked that your throttle lever is fully engaged in the neutral position. Once in a blue moon I had to "jiggle" mine in the neutral position to get the ignition switch to work.

I understand your response........ but to add a bit of clarity;
Regardless of the Neutral Safety Switch position, the ignition portion will still work.
It's the S circuit that is disrupted when not in Neutral.

[builderdude]

He meant the ignition switch me thinks😁

[builderdude]

I'll check all of those tomorrow. Thanks! I did replace the slave solenoid last week as well as the starter, spark plugs and wires, distributor cap and ignition coil.

With a new starter and slave solenoid Id think you likely have a wiring issue.
The back side of ignition switch has 3 terminals. “B” battery (red or red/purple),
“I” ignition (purple),
“S” start (yellow/red stripe)
You should see DC voltage at the small yellow/red terminal at the slave solenoid while the key is in the “start” position. If you don’t see voltage there the issue is “upstream” from the slave, bad wiring connection or bad ignition switch or improper wiring there.
If you do see voltage there your new slave solenoid should close the circuit (two larger terminals of the slave) passing voltage onto the starter motors solenoid.
Yes, two solenoids in the system, slave solenoid & starter solenoid.

SLAVE SOLENOID
A & B are the large terminals that handle the heavier amperage draw of the starter motor.
C & D are the smaller terminals that “trigger” the slave solenoid to close. (D needs to have a solid connection to DC negative).


STARTER SOLENOID
This is the actual starter motors solenoid & it’s related wiring.

[estecks]

Are you getting power to the slave solenoid that’s mounted on the engine? Do you have the wiring diagram for your engine?

[estecks]

With a new starter and slave solenoid Id think you likely have a wiring issue.
The back side of ignition switch has 3 terminals. “B” battery (red or red/purple),
“I” ignition (purple),
“S” start (yellow/red stripe)
You should see DC voltage at the small yellow/red terminal at the slave solenoid while the key is in the “start” position. If you don’t see voltage there the issue is “upstream” from the slave, bad wiring connection or bad ignition switch or improper wiring there.
If you do see voltage there your new slave solenoid should close the circuit (two larger terminals of the slave) passing voltage onto the starter motors solenoid.
Yes, two solenoids in the system, slave solenoid & starter solenoid.

SLAVE SOLENOID
A & B are the large terminals that handle the heavier amperage draw of the starter motor.
C & D are the smaller terminals that “trigger” the slave solenoid to close. (D needs to have a solid connection to DC negative).


STARTER SOLENOID
This is the actual starter motors solenoid & it’s related wiring.

Does the purple wire (IGN) go to the fuse box to draw power? Or where does that one go from the ignition key?

[2850Bounty]

.......

Does the purple wire (IGN) go to the fuse box to draw power?
No, the purple wire receives power from the rear of the key switch "I" terminal, when in the "run" position only.

The yellow/red stripe wire (the S circuit) receives power when the key is in the start position only!
That same circuit is either interrupted or NOT interrupted by the Neutral Safety Switch.

Or where does that one go from the ignition key?
Actually, that would be the key switch!

It goes from the key switch to the hull harness, then from the hull harness to the engine harness, where it makes it's final connection.

FYI and by the way:

The slave solenoid is there to circumvent an otherwise lengthy (as in from the helm back to the engine) "S" circuit!
Length = resistance!
The starter motor is Amp Hungry, and will lower the voltage required to actuate the starter motor's solenoid.
The slave solenoid requires less current to close the contacts.
By using a slave solenoid right at the engine, the shorter S circuit now has more current.
This allows the starter motor's solenoid to have enough current to push the pinion gear out, and to close it's contacts.

[builderdude]

Does the purple wire (IGN) go to the fuse box to draw power? Or where does that one go from the ignition key?

As Rick stated, the purple wire receives power from the rear of the ignition switch "I" terminal when the ignition switch is in the "run" position. It energizes the gauges and the ignition coil.

[2850Bounty]

As Rick stated, the purple wire receives power from the rear of the ignition switch "I" terminal when the ignition switch is in the "run" position. It energizes the gauges and the ignition coil.

Dave, Good catch! My bad..... I forgot to include the gauges!

On some models, it also energizes the alternator field.

Please help me diagnose the problem. I'm guessing a wiring problem.

estechs, try using the P of E.... (process of elimination).

Check/test/confirm/eliminate/replace one suspect item ONLY at a time.
Only after that item proves to be OK, or NOT OK, do you move on to the next suspect item.


Start at the rear of the key switch.

With your MBSS ON, check for power at the + terminal.

Turn to the "run" position, and check for power at the "I" terminal..... the instruments should power-up.

With safety measures in place, turn to the "start" position, and check for power at the "S" terminal.

Again, with safety measures in place, and with the Throttle/Shift lever in Neutral, check for power at both sides of the Neutral Safety switch.
If only one side is powered, the switch is either bad, or it is not adjusted correctly.

Pull the Hull harness-to-Engine harness connector apart, have a helper turn the key to the "start" position, while you check for power at the "S" circuit pin.

Plug the harness back together, again have a helper turn to the "start" position, while you check for power at the Yellow/Red Stripe circuit at the triggering side of slave solenoid.

Repeat the above, and check for power at the starter motor's "S" terminal.

If "S" circuit power makes it this far, you have either a bad starter motor solenoid, or a bad starter motor.


************************************************** *

I did replace the slave solenoid last week as well as the starter, spark plugs and wires, distributor cap and ignition coil.

For a non-seasoned Marine Mechanic, I suggest that we never replace more than one part at a time.

Test that newly replaced part, or component, before moving on the next replacement.

Q: Why?
A: If there is an issue, rather than guessing at which one it could be, you'll know exactly which component had been changed



.