Starting Issue - Need Ideas!

L

ljaynavl

Junior Member
Problem: Starter motor can barely turn over the engine.

Background: Tried two starters that check out fine. We’ve tried hooking them up straight to both 6 volt (used on car) and 12 volt. Starter motor cranks just fine when connected directly to battery.

Battery in the car is new and checks out fine under a load test.

Ground connections cleaned. We’ve tried adding a supplemental ground.

Tried swapping the starter switch.

Removed plugs – oddly that allows the motor to turn over without issue!

Would really like to read some suggestions as to what to try now.
 
What's the history of the two starters? Ordinarily I would say two starters doing the same thing would rule that out, but this sounds like a classic "weak starter motor" problem. Replacing the starter tends to solve it.
 
You mentioned supplemental ground. Did you run a heavy battery cable directly to the bell housing near the starter from the positive battery terminal?
 
Drive a nail into the crimp between the wires of the cable and the negative battery connector. Corrosion can get in there and fool you. Either crimp it a lot more or use the nail trick.
 
Dad's 67 Chevy pu he put a screw between the battery post and the cable end, when it wouldn't turn over just tighten the screw more. I got tried of this and replaced the cable, got one off the shelf at his store, squeak squeak tight as bark on a tree! We charged gas at one station and one time he didn't like the bill and said no more charging! Well the truck drank gas bad and one night dad was gone I rebuilt the carb, dad asked one Friday night going home why he still had gas in the tank, I said cause I rebuilt the carburetor he then said we can again charge gas at the station!
 
Use a voltmeter to give you an idea about where the problem is. Put one lead on the + battery post, not the battery clamp, but the post itself. Then put the other lead on the case of the starter. If you get much voltage drop then you need to find out where its dropping, keep moving the lead from the starter case back towards the battery until you see where its dropping. Do the same thing with one lead on the - post and the other on the starter contact, and on back. First thing of course, would be to check the battery dip, right on the posts.
 
Bob from Northport said:
Check the timing. Make sure the crank/timing gear are not out of sinc causing hard turn
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I don’t think this is true. I don’t see how timing would or could influence whether the starter would turn the engine over. Can you explain that, Bob?
 
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Try starting a cold engine without retarding the spark. The motor/and starter will drag, especially if it is not timed right. If the timing is way off, the motor will try but very hard to roll, but won't. The compression and exhaust cycles in the cylinders would be off
 
Off timing will not increase compression. A good starter and proper wiring is all that is needed plus a good battery to get the engine rolling.
 
700rpm said:
I don’t think this is true. I don’t see how timing would or could influence whether the starter would turn the engine over. Can you explain that, Bob?
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If the timing is too far advanced, as each cylinder comes up to compression on the starter, it fires before the piston is at the top. That puts enormous strain on the starter which is fighting the explosion in the cylinder.
 
Synchro909 said:
If the timing is too far advanced, as each cylinder comes up to compression on the starter, it fires before the piston is at the top. That puts enormous strain on the starter which is fighting the explosion in the cylinder.
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That is of course true, but the op was having trouble with a slow starter and didn't mention any combustion. He could remove the plug wires to test your theory by leaving the plugs in and seeing if it makes a difference.
 
You don't mention anything about the condition of the engine. Was it just rebuilt? Was it run with low or no oil recently? Did it severely overheat recently?
 
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