Gentlemen,

So, in the conyinuing saga of replacing my starter motor - - I installe a brand new one. Not a rebuilt. Brand new. Started right up the first turn of the key.

Went out around town. Started again after stop 1. And again after stop 2. And again after stop 3.

But after stop 4 - there was some swearing. Turn the key, load clunk of the solenoid actuating, and the obvious whirrr of the starter spinning, but spinning fast, like it's free, and not turning over the motor.

I thought, maybe, there;'s something about the teeth, it can't engage, so I turned the crankshaft just a tooth or two of the flywheel - same thing. Connected one cable of the jumper cables to the battery positive, and climbed under the truck with the other end. Touch it to the solenoid control post, and it acutates. Touch it to the motor positve feed, and clearly the motor is spinning fast and free. Turn the key, same thing - solenoid clunks, motor spins free.

So I took it off the truck right there in the parking lot and re-installed it. You never know. No change.

So I got a friend to come get me and take me to a local parts shop who gladly sold me a rebuilt starter, which I installed there in the parking lot while it rained a river under the truck. First turn of the key, engages, turns over, and starts.

What kind of failure can lead to what happened?

Thanks.

 

Sometimes you just get unlucky and get the lemon of the batch. Now will you be able to get a refund on the new defective starter?

 

Oh ya, I nkow it was just a lemaon that failed. But I'm wondering what, mechanically, happened? How can the solenoid engage and the motor spin without it turning over the engine? Is there some kind of clutch in there that may have failed? Drive shaft broken?

 

There is a one way clutch on the pinion gear. I've only replaced one starter so far with a bad 1 way clutch. It made a sound similar to when the pinion gear grinds against the flywheel gear.

 

Yes, in most starter designs there is a one-way clutch between the motor shaft and gear. Also, many older Ford starter designs had a mechanism called a Bendix spring that threw the drive gear out to engage with the ring gear. Those used to go bad frequently.

Jim

 

First of all, never, ever try to actuate a starter while you're underneath the truck. Just don't do it.

Lastly, this sounds like a solenoid-mounted starter. If so, it won't have a bendix. It's a PMGR starter. Sounds like you got a bad one.

 

The solenoid mounted starters are the ones that have a Bendix drive. The old style Ford starters had a movable field shoe that would pull down once current was flowing and a magnetic field built up. This would move an arm, which would kick out the starter gear.
Newer integrated solenoid starters have a plunger that has the contact plate on one end, and an arm on the other to kick the gear out once the solenoid is actuated.
Either one of these designs can have the exact problem yours had if a simple little roll pin falls out.