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 Posted: 01-02-2018 12:28 am
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 320
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Dave,

I have no idea what to say about the old alarm system, or any loose wires that may have resulted from removing it. Ignoring that may be over-looking the problem, but that's all I can do for now.

Have you stripped down and cleaned the carbs? That has nothing to do with getting the starter to turn-over more than a turn; however, I can just about guarantee that the carbs are gunked-up by 25 years of sitting around, whether Z-S or Dellorto. And if they're Z-S, I'd also be concerned about the condition of the rubber diaphragm that runs the whole show.

Without addressing the carbs first, I suspect that even when you get the starter to crank continuously, the engine won't start for lack of a combustible mixture.

Since the starter repeatedly cranks a turn, then quits, it may be that there's a bad spot on the commutator, or in one of the armature windings. The motor may require a rebuild, but before you go that far, try jumping the starter solenoid directly. Doing so will eliminate the rest of the car's electrical system and all the dangling wires. With direct power, the starter motor will run or it won't.

Start by removing the battery cables by disconnecting both ends and physically removing the cables. Clean the battery terminals. Use heavy gauge jumper cables to re-connect the battery.

Use the black cable to connect the battery's (-) terminal directly to the engine block... not to the chassis ground. If you can (try hard), clamp onto the block's rear flange where the starter bolts on, such that one jaw of the clamp actually bites down on the starter motor's rear flange.

Use the red cable to connect the battery's (+) terminal directly to the threaded brass terminal on the solenoid (where the red battery cable was formerly connected).

Make certain the transmission is in neutral. Then use an old screw driver you don't care about to bridge between the red battery cable on the solenoid, to the solenoid's small, 1/4" spade terminal where the white/ red stripe wire previously went. There may be an arc when the screw driver makes contact with the terminal. Don't freak out... and that's why you're using an old screw driver you don't care about.

If the starter is ever going to run... it should run now. If it doesn't...

1) The solenoid could be bad. But since the starter has been running one turn at a time, I'm thinking the solenoid isn't the problem.

2) The ground connection between the starter motor housing and the engine block could be corroded and not making electrical contact... ie, where the joint/ connection where the starter bolts to the engine block. I've "fixed" several starters that wouldn't run simply be cleaning that joint. Remove the starter. Clean the rear flange with a wire brush. Similarly, clean the mating flange on the engine block. Apply a light smear of copper Anti-Sieze to both mating faces, and bolt them back together.

Number 2) is why I recommended that you attach the negative jumper cable to the engine's rear flange such that the jaw also bites directly on the starter's mounting flange. Presuming the connection between the starter and the block is corroded, try to attach directly to the starter motor housing or a mounting bolt.

Do all of that...

3) If the starter still doesn't run, then remove the starter and take it in to an automotive electric repair shop. Worst case (??), replace it with a new one. If you go that route, then I strongly recommend one of the aftermarket Gustafson geared starters that are available from Delta Motorsports, JAE, or Dave Bean Engineering.

4) If the starter runs when directly jumpered, and when the solenoid is directly shunted to 12 volts, then you've confirmed it's not a starter problem. Then, if you remove the jumper cables and re-install all the original wiring, and the starter reverts to not working, then you can be pretty confident that there's a problem in the wiring harness. Good luck with that... I hate electrons... or, at least working with them.

One easy thing to check is the chassis ground. The black cable from the battery's (-) terminal goes to the chassis ground point. Then a braided cable jumps around one of the rubber engine mount (usually the right), and connects to the engine-side of the mount. If that braided cable is missing, broken or has a poor connection, then the engine is isolated by it's rubber mounts, and not grounded. That would affect all engine electrics, including the starter.

I like to buy a heavy gauge black cable with eyelet terminals on each end. Not one of those little pencil-thin cables, but a real, manly cable (ALL battery cables in the car should be 'manly'). Then run it from the chassis ground (where the black battery cable connects) to one of the starter mounting bolts. That will ground both the engine and the starter, and give the most direct ground possible to the starter motor.

Regards,
Tim Engel