My wife,s 54 Chevy is getting harder to start after driving a few miles it turns over real slow. I put a volt meter on the battery while at rest and it read 6.5v, fired it up and checked it at idle speed and got 6.7v then reved it up some and got a best of 7v, is this right?
Check your grounds. Good grounding is always important, but is very important on a 6V system. A bad ground has a larger affect on a lower voltage system.
To add to the good tips, make sure the battery cables are not the same size used for 12 volt-they need to be extra thick. Six volt systems are very unforgiving with any voltage drop or resistance.
With the engine at about 1500-2000 rpm there should be about 7.4 volts with lights on or off. If the cables and all that are correct,the starter motor is tired..
My 37 Chevy pickup was hard to start after it had run awhile and it was worn starter bushings allowing the armature to drag when hot.
Sounds about right. As others have pointed out, first check that all connections are clean and tight, 6V systems are touchy about this. And of course that you have the right size cables. If this doesn't fix it take the starter to a local rebuilder and have it rebuilt. They will do a far better starter than the parts store rebuild, for the same money or less.
Nobody else asked so I will. How old is the battery? If it's over 4 years and the sides are starting to bulge out it's time for a new one.
6V systems are all about resistance. Clean and tight connections, and good grounds are the first thing to look for, proper sized primary cables are a must, minimum 1 gauge, and make sure the connections for the primaries at the solenoid are clean and tight, and just for piece of minds sake a ground from the firewall to the frame isn't a bad idea either. Voltage regulators for these cars are all about putting back into the battery what has been recently used, once that is complete the VR basically lets the generator freewheel until there is a need for more juice. So if your battery is new and in a good state of charge your VR may be doing is job properly as the Battery doesn't need a lot of charge to restore it back to pre start level. The good news about the VR is that most are adjustable by tuning the points gap for the cutout circuit. Also popping the cover of the VR and dressing the points with a points file couldn't hurt. The last thing to look at is the starter bushings. As mentioned above they usually wear oval and allow the armature to drag against the field coils causing drag. But I would go after the electrical stuff first, as it the easiest and most likely problem area.
Starter solenoid could be shot too. Remember, these things draw big current, and if that wafer in the solenoid is dirty then there will be resistance which slows down the starter itself. Another issue: is the engine gunked up with sludge and the oil is thick as mol***es? Any little thing will slow down cranking speed.
Here is something that no one has mentioned, I have had 3 batteries fail in the last two years. All of them would charge to the proper voltage and they all failed because while they would charge to the proper voltage they would not pull the amps it takes to turn a starter. All it takes is one weak cell. A quick check, remove the caps from the battery. Now take your multi-meter and with it set on OHMs measure the resistence from one cell to the next. Pay attention to the numbers that you are getting. The weak cell will be obvious. Be sure and wipe your leads down good after your test battery acid is hard on them. yea I know it is backyard but it works.
What is the cranking voltage? Also do you have one of the battery disconnect that is attached on the battery post? This gave me a problem.
Thanks for the info guys, cables are all in good order and the battery is about 3 years old, engine has about 4000miles on it. I,ll get the starter checked over.
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