Started issues

[NH TOONER]

I was having starter issues so I thought the started needed replacement. I changed the starter with a high torque one. When I turn the key the starter spins fast but the drive doesn't kick in. What does the slave solenoid do? and why is it there? I have a 1980 stringer. 350 motor.

 

[RicardoMarine]

I was having starter issues so I thought the started needed replacement. I changed the starter with a high torque one. When I turn the key the starter spins fast but the drive doesn't kick in.
See images below.

What does the slave solenoid do? and why is it there?
The slave solenoid is not completely necessary, IMO. Many systems do incorporate this however.

Nonetheless, the main solenoid on this type of starter motor, serves a dual function.
1.... it acts as the kick-out device for the pinion gear into the flywheel ring gear.
2.... if serves as the main electrical contact for the armature.

First action is the "kick-out", once completed, the contacts close, and the armature spins.

I have a 1980 stringer. 350 motor.

All GM V-8 engines are machined for both flywheel size starter motors..... (I.E., the straight across and staggered bolt patterns).

If you have the 153 tooth flywheel, and you bought a starter motor for 168 tooth flywheel, the pinion gear will not reach the flywheel ring gear.
Conversely, if you have the larger 168 tooth flywheel, and you bought a starter motor for the 153 tooth flywheel ring gear, the pinion gear will be forced into the flywheel, and will not mesh with the ring gear.

I'm not suggesting that this is indeed your problem, but it's certainly a place to begin.


Here's the correct motor for the smaller 153 tooth ring gear.
Note the straight across bolt pattern.

Here's the correct motor for the larger 168 tooth ring gear.
Note the staggered bolt pattern.

Make dang sure that you check the new bolt length against the nose housing.
Many of these nose housings vary in bolt length bores.
Wrong bolt lengths.... and the bolts may bottom out prior to fully clamping the nose housing to the engine block.


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[NH TOONER]

It is the same bolt pattern as I removed. And used new bolts that came with it. Bolted right in with no problem. Just not kicking in the drive.

 

[RicardoMarine]

This is NOT a HTGR/PMGR motor, but the solenoid kick-out action is very similar to one.

While it's tough to see, the pinion gear must reach out fully prior to the contacts closing.
IOW, if the armature is spinning, the pinion gear will typically be fully engaged into the flywheel ring gear.
There would need to be a rather severe malfunction for it not to.

Its a bit easier to see in this image.

 

[RicardoMarine]

One other possibility would be a ring gear with a few teeth missing in one area, or severely worn teeth in one area.

Turn the engine over by 20 degrees or so, by using a strap wrench on the harmonic balancer, and give another try.


.

 

[NH TOONER]

I already did turn the motor by hand. Starter spins fast but not engaging the flywheel . The started I took out and the one I replaced both have the straight bolt pattern. that's why I thought the slave solenoid might have something to do with it. I cant understand why that slave solenoid is even there. Maybe my new starter is bad?

 

[RicardoMarine]

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

I already did turn the motor by hand.
Hmmmm!

Starter spins fast but not engaging the flywheel .
Unlike a Bendix Drive starter motor, these use a Sprague Clutch arrangement at the pinion gear.
This is a one-way clutching device that allows the pinion gear to be armature driven in one direction, and to free-wheel if it was to remain engaged in the ring gear.

I wonder if it's possible that the Sprague Clutch is bad.


The started I took out and the one I replaced both have the straight bolt pattern.
Do you still have the old motor?
If so, hold them side-by-side, and compare the location of the center of the pinion to the bolt pattern.


that's why I thought the slave solenoid might have something to do with it.
Not sure how yours does it, but with the Mercruisers, the slave provides power to the starter motor's "S" terminal only.

If it's engaging at all, the slave solenoid is working.





I cant understand why that slave solenoid is even there.
I believe that it's used due to the "start-by-pass" circuit to prevent any feed-back from the ignition circuit.

Maybe my new starter is bad?
Possibly.

 

[RicardoMarine]

Kim, if I'm understanding his first post, the new starter motor is receiving power, and is turning over, but is not engaging.

When I turn the key the starter spins fast but the drive doesn't kick in.

 

[RicardoMarine]

Well.... here's the deal as I see it.
If the starter motor armature is turning, the main contacts will have closed.... which means that the pinion gear can't help but to have been "Kicked-out".
Unless of course the motor or the sprague clutch was bad from the get go.

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[RicardoMarine]

My buddy has a 85 stringer that will do the same thing with a low battery.

Your buddy may have a Bendix Drive starter motor.
The Bendix Drive units require full voltage to produce the quick armature torque that kicks the pinion gear out.

With the solenoid style starter motor, if the contacts have closed, (unless the lever arm has broken) I can assure you that the pinion gear has already been kicked out.




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