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I have a brand new battery in the truck, fully charged. When I try to start the truck the starter turns very slow and quickly kills the battery. On the bench fully charged the battery reads 6.4 volts, which is normal I believe. Would this be a battery issue? Or could it be related to the starter? The starter will turn just not very long.

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How hot do the batt.cables get? I had original 0 cables on the '49 that looked ok, rebuilt starter dragged in the truck but bench tested fine, engine could be turned over with 30 ft-lbs on crank nut...on a hunch, I split open the cable insulation at their midpoint to find the copper strands black with oxidation, which was driving the starter circuit impedance sky-high. I made some new 0 cables, and that starter really came to life...you might be in the same boat :cool:

Edited by JBNeal

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The cables are brand new I'm not sure which gauge I bought honestly. What gauge should the battery wires be?

1 is OEM anything thicker is better

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I'm thinking i bought 4 so I should probably upsize

If you just went to the auto parts place and grabbed off teh shelf cables they are most like way too small. Go back and ask for 1 or better. I know a lot of guys run even bigger but I have 1 gauge on both my oldies and they work great.

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So 1 or 0 would be preferred? Could this possibly be the problem? The starter just is not getting enough power

go 0 if you can. Might not be the entire problem but its certainly contributing.

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Suggest when starting you spin your starter in short 5-6 second bursts. Then wait 15 or so seconds until you hit it again for another 5-6 seconds. Continual cranking with the starter motor builds heat and the heat increases resistance making everything work harder and slower. I cringe when I hear people continue cranking the starter motor until it darn near quits. Give it a break and let it cool down.

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Ok I'll start there thank you for the suggestions and information. Could the starter itself be the issue? I can get the truck to start just off the starter but usually need the battery charger hooked up also.

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Suggest when starting you spin your starter in short 5-6 second bursts. Then wait 15 or so seconds until you hit it again for another 5-6 seconds. Continual cranking with the starter motor builds heat and the heat increases resistance making everything work harder and slower. I cringe when I hear people continue cranking the starter motor until it darn near quits. Give it a break and let it cool down.

But if my battery already has 6(six) years? *Observation:my three old cars run not daily.(stopped some weeks or month)

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Like others have said the heavier gauge cables are needed for the 6 volt system.  Also, make sure your grounds are good and clean.  Depending on whether or not those two things change anything, you may want to pull the starter and take it apart to inspect the brushes, springs,  and clean the commutator (those things could all be contributors too).   If you have a volt meter, while cranking the motor see what your battery voltage drops to.  You may have a week battery that is failing under a load.   Mike

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Full charge is 7.2 volts for a 6 volt battery.  Was the battery dead ?  if so, it maybe Sulfated.  If it is it will need to be slowly run flat and recharging may recover it, if not check the starter motor commentator and brushes it they are corroded they will need to be cleaned.  Check your ground between the engine and the battery post.  Check the starter switch, inside where the contacts are, any fouling will need to be cleaned.  Check the specific gravity of the electrolyte, should be around 1275.  When you find it, it will be an easy fix.  Keep on Trucking.  Charlie

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52 b3d, I have a brand new battery, it's fully charged. I put it in the truck and try to start it. It cranks strong for a couple of seconds then quickly dies and fails to start the truck. The only way the truck will start is when it's on the charger. All the wiring in the truck is brand new, the generator and the voltage regulater are all brand new. What could be my issue? Almost seems like there is something else taking a big draw on the battery.

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If the battery is good and fully charged up you can do a very simple test. Leave the battery disconnected and make sure everything is turned off and then hook up the ground cable. Then just lightly brush the other cable to the other battery terminal........if you get any kind of spark then there is a load on the system. If this is the case then you need to isolate the item that is draining your battery. This is very old school but I have used it over the years with good results.

 

Jeff

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Have you upgraded the battery cables yet? If the cables ate too small, or if you have old cables with a lot of corrosion, or if you have poor connections, it could be causing extra resistance which leads to more voltage drop at the starter and slower cranking.

What is the voltage at the battery when cranking? Then what is the voltage at the starter when cranking?

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I have not upgraded the cables yet I am planning to do it soon, just got very busy. I also am having a hard time finding some of the connectors to build my own cables. On a side note I have the ground of the battery grounded at the bottom starter bolt, would this be a problem? I will try to get those readings and repot back.

Thanks for the replys

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