Starter motor won't turn on

[MrBrownAndSon]

1997 Ciera 2655 Merc 5.7L Alpha1 Gen2…Boat sat for over 10 years

Ok, so I can turn engine by hand (Marvel Mystery Oil in cylinders, soak for days, plugs removed, then attached tool to balancer and with ½ in breaker bar engine now turns).
I replaced the starter “relay”… the starter still didn’t crank when I turned ignition key.

I attached a remote starter button (one lead to positive post on battery, the other lead to the small post of the starter solenoid (a yellow and red wire was attached there)….pressed the button and nothing. I verified with multimeter that the remote starter lead at the solenoid had 12+ volts.

My research implies the starter is bad and should be replaced/rebuilt based on the above (I don’t want to mis-diagnose so I’m posting the question. Based on the test setup do you believe the starter is bad or do I have to keep digging?).

Did I miss something? Was the remote starter properly attached? My question is: can a starter go bad from sitting for so long, or is it more likely to have been damaged when I attempted to start a seized engine?

No prob if the starter has to be replaced, I want to make sure before proceeding.

Thanks,
Don

[Nauti_Mike]

Remote start? Is this something you connected or are you referring to the engine breaker in the harness? If the later this is a breaker that provides the engine and helm power. Next to it should be the slave solenoid, try jumping across its two big terminals.

[builderdude]

Remote starter button me thinks

[builderdude]

A starter can be damaged by an attempted start to a seized engine, it generally fractures the nose cone of the starter and potentially causes the armature to bind up within the motor. The small post with yellow/red wire is in fact the trigger. I’d suggest removing the starter for a visual inspection and or a bench test.

[MrBrownAndSon]

Remote start? Is this something you connected or are you referring to the engine breaker in the harness? If the later this is a breaker that provides the engine and helm power. Next to it should be the slave solenoid, try jumping across its two big terminals.

It's a remote stater button as BuilderDude surmised.

[MrBrownAndSon]

A starter can be damaged by an attempted start to a seized engine, it generally fractures the nose cone of the starter and potentially causes the armature to bind up within the motor. The small post with yellow/red wire is in fact the trigger. I’d suggest removing the starter for a visual inspection and or a bench test.

After all the work I'd completed so far to bring the boat back to life, I was hoping and praying that it would at least crank. After I installed the new set of manifolds/extensions/elbows I attempted the start...I should have checked to determine if the engine was seized. I did not. At this point I only want to understand what caused the starter motor to die if it is indeed dead.

I'll pull it off and perform the bench test as suggested to be 100%, but I think I'd feel better placing my order for a new starter motor to replace this 25 year old one.

[MrBrownAndSon]

BTW: when I first attempted to start the engine all I got was the dreaded loud single "click". Keeping true to my tendency to mis-diagnose, I figured the reason for it not cranking was a bad "relay". The 25 year old relay has been replaced...it might actually be ok but it's still 25 years old.
.

[builderdude]

I busted my starter attempting to crank through a hydro lock so shit happens🤪
Mercruiser will actually use what we call a slave solenoid. Is this what you replaced?

[MrBrownAndSon]

Thanks Dave, yes, I've been attempting to use the correct terminology to eliminate confusion. "Slave solenoid", "Starter relay", "Solenoid" all being used randomly.

Yes, your picture shows what I replaced. It clicked loudly once when I attempted to start the engine. That's the part I replaced, and then worked to free the engine. After it was replaced, I no longer got the single click...instead I got "silence", nothing. so I figured the "relay" was not the problem and attempted the remote starter test to bypass all intermediate components.

The component attached to the starter is the actual true "solenoid" correct? I'll pull the starter off tomorrow and post the results of the bench test.

[builderdude]

The component attached to the starter is the actual true "solenoid" correct? I'll pull the starter off tomorrow and post the results of the bench test.

Yep, that’d be the starter solenoid.

[builderdude]

Also: with a potential inoperative starter motor you should still hear a click from the slave. Double check your wire connections at the slave also including battery cable connections both positive and negative at both ends are clean and solid.

[2850Bounty]

...................

Thanks Dave, yes, I've been attempting to use the correct terminology to eliminate confusion.
Don, my hat is off to you. Quite often the correct terminology is not used.
And you are correct..... when the correct terminology is used, it does improve communication and it certainly helps to eliminate confusion.

"Slave solenoid", "Starter relay", "Solenoid" all being used randomly.
With anything other than the old Bendix drive starter motors, the solenoid unit on the starter motor serves a dual function:
It is a "contactor" as it simultaneously serves as a mechanical device that kicks the pinion gear out and into the flywheel's ring gear.
Technically speaking.... the mechanical kick out function precedes the contact function.

Think of the "slave solenoid" as a "relay" for the S circuit (from the helm, through the harness and back to the actual starter motor).

Yes, your picture shows what I replaced. It clicked loudly once when I attempted to start the engine.
The "clicking" sound indicates that the solenoid's magnetically operated plunger is working.
What is apparently NOT working, would be the contacting portion of the solenoid.
Or..... while sitting for over ten years, some corrosion has occurred between the commutator and the brushes, causing loss of continuity.
In other words, the solenoid may be contacting correctly, but the current is not reaching the commutator.

Occasionally, a few gentle taps on the starter motor housing get's things going again.

That's the part I replaced, and then worked to free the engine. After it was replaced, I no longer got the single click...instead I got "silence", nothing. so I figured the "relay" was not the problem and attempted the remote starter test to bypass all intermediate components.

The component attached to the starter is the actual true "solenoid" correct?
Correct!
Several companies began to include the slave solenoids in an attempt to reduce line loss (resistance) in the S circuit.
Why the heavy Amp solenoid was used ..... I'm not sure. It could just as easily have been a smaller relay switch.

I'll pull the starter off tomorrow and post the results of the bench test.
Try to NOT allow the armature to spin freely at high RPM.

Don, your 1997 engine should be equipped with a HTGR/PMGR starter motor.
If you replace the starter motor, be sure to use a similar starter motor, and be sure to get the correct bolt lengths.

Here is a HTGR/PMGR unit.
Armature vs pinion gear spins approx 3:1












Here is an older Non-Gear Reduction starter motor.
Armature vs pinion gear spins 1:1
Heavy amp draw, and will not spin the flywheel nearly as fast.

[MrBrownAndSon]

Thanks for the additional clarification, Guys.

I pulled the starter motor and attempted a bench test. Nothing happened, and I verified that the setup was correct (Cleaned all posts, then made connections from Battery pos to big post on starter, from Battery neg to starter case, verified 12+ volts present at starter, then Jump from big post to small “S” post on starter).

To be 1000% absolutely positive, with no questions, I took the starter to a Starter/Alternator shop. They verified immediately that the starter was no good.

2850Bounty: that’s a very pretty starter that looks just like mine. I believe the oem part number is:
50-863007A1

That’s what I’ll use to order the replacement. It still would be nice to know why it died but I can live with the fact that the shop verified it’s condition (for free btw) and didn’t attempt to sell me anything).

Thanks for the explanations, it helps, however, I’m not comfortable with having to give the starter motor a few whacks to get it to respond. If it needs to be whacked, then it needs to be replaced, lol.

I’ll send a final reply to the thread once I receive and install the new part.

[MrBrownAndSon]

A starter can be damaged by an attempted start to a seized engine, it generally fractures the nose cone of the starter and potentially causes the armature to bind up within the motor. The small post with yellow/red wire is in fact the trigger. I’d suggest removing the starter for a visual inspection and or a bench test.

Also, BuilderDude, is it possible that my starter is an automotive one? It has three posts as opposed to 4. I do not have an electric fuel pump, and all of the new replacement motors have 4 posts as depicted in your reply.

Would I be able to leave that fuel pump post disconnected?

Thanks, hopefully this is last question before I receive and install the replacement.

Don

[builderdude]

The I terminal can be left alone, it’s used as a ignition bypass circuit on some systems and fuel pump bypass circuit on others.

[MrBrownAndSon]

Thanks, I thought so but wanted to be sure. The starter replacement should be here early next week, I'll post an update once it's installed.