Detroit Diesel 3-71 starter removal help

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k_kindig11

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Oct 21, 2020
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I believe the starter went out on my Detroit Diesel 3-71, model 3055-C. I took the cables off and got the three bolts out that hold the starter in place. When I try to slide the starter back and out of the pocket where it engages with the flywheel, it doesn't seem to have enough room to get it out. Does anyone know if other parts need to come off the motor to get the starter out or should the starter be able to slide out (tight, but come out) without taking anything else off? I have attached a picture of a motor I found online as I forgot to take a picture and it's dark out now, but you can see there isn't much room to slide it out since the starter has a domed portion that is inside the pocket in the motor where it engages with the flywheel. There is a filter housing below the starter that keeps it from going down and a water pump housing on the back side. Any help would be GREATLY appreciated. I just want to make sure I'm on the right path without making a bunch of unnecessary work. Thanks!
 

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Also found this picture that has the starter removed. Makes me think it should come off without anything else needing removed...?? Thoughts?
 

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Is it mounted with studs or bolts?

Ted
 
They are bolts. Also attached is a picture of my motor. The solenoid is separate from the starter. You can see just a piece of it in the upper left of the pic. I tried to engage the starter by bypassing the solenoid with jumper cables, going directly from battery to positive and neg on starter. Shouldn’t that turn over the starter if it’s working properly? It sparks but doesn’t do anything.
 

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For some reason the forum flipped the picture so the solenoid in the picture as shown is at the bottom left. Just a portion is captured
 
If you touch the jumper cable briefly directly to the starter motor (not the sol) it should spin freely. You should hear it spin up and coast down. The solenoid has an internal lever that thrusts the starter gear against the engine flywheel. If nothing happens but sparks then the motor has issues. Pull it out and take it to an auto electric shop.
 
My solenoid isn’t located on the starter so it doesn’t have that lever inside. Not sure how mine works.. It is a good distance away. It’s an old girl. But yes I tried taking power directly to the starter and I don’t hear anything - no spinning at all which made me think it was the starter that was the problem. I’m wondering if it’s stuck out, engaged in the flywheel, and that’s why I’m having trouble getting it out....? A thought
 
Just pull it and take to a shop then.
 
Just pull it and take to a shop then.


That is what he is asking about, removal. It won't come off the engine.

I have not worked or see none so these are guesses.
So you can pull it backwards, correct? Have you tried rotating it? Sometimes things have to be rotated out of or into position.
 
You might check on boatdiesel.com and see if there is any info there. I think it costs $25 a year to be a member.
 
The starter needs to slide back about 3-4" to clear the housing. That means you need to remove part of your cooling system that's in the way.
 
Looks like it would bump into the oil cooler. May need to drain the coolant and take the cover off to get a bit more clearance.

Before you do that, wiggle the heck out of the thing as there may be an orientation that clears.

Those starters come in various lengths, might be able to get one an inch shorter with same nose and pinion.

And be dang sure the starter is the problem. Sounds like that is not really known yet.
 
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Ski,

Can a 3-71 be barred over? Could be something like a damper plate broken spring jamming up the engine. Is that possible?
 
My solenoid isn’t located on the starter so it doesn’t have that lever inside. Not sure how mine works.. It is a good distance away. It’s an old girl. But yes I tried taking power directly to the starter and I don’t hear anything - no spinning at all which made me think it was the starter that was the problem. I’m wondering if it’s stuck out, engaged in the flywheel, and that’s why I’m having trouble getting it out....? A thought

I think you are going to have to remove the oil cooler so you can slide it back further to remove it. It looks like a Bendix drive starter where the pinion gear slides out when the starter spins.
 
Ski,

Can a 3-71 be barred over? Could be something like a damper plate broken spring jamming up the engine. Is that possible?

Yes, there is a bolt on the front of the crank. Comes in various sizes, so need to experiment with what fits. Should bar over with some force on a 2-3' breaker bar. Go in the tightening direction even if engine is rev rotation. Don't want to loosen the bolt.
 
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