The Stovebolt Site Forums The Shop Area The Electrical Bay starter moter current draw

I've got a '47 Chev. Loadmaster, I can't get any spark. I've repalaced all the obvious "tune-up" parts (points, cond., cap, rotor, coil) and still nothing. I checked my voltage at the coil with ign. switch on, I have 7.5 volts, while cranking the engine over, I have 5.5 volts. Is my starter drawing too much current and not leaving enough for the ignition? (I did this test w/plugs removed to reduce compression and reduce strain on the starter)

That sounds pretty typical, but check your battery cables for corrosion. 6V systems need twice the current for starters so I like to use 2/0 or 4/0 battery cables instead of the ususal #4 or #2 12V battery cables you get at the auto parts store. This greatly reduces the voltage drop across the cables.

You may want to do the spark plugs too, when I first got my truck it wouldn't start until I replaced them and then it fired right up.

Thanks I'll try the battery cables and see what happens, I forgot to mention plugs, wires, and starter motor brushes are new, maybe cables are the the last thing on the list. This is my first time in the forum, I've been on the site many times looking in. I've found your own experience combined with the experience of others with the same interests is better that some old shop manual.

Did you check the voltage at the - side of the coil when the points are closed? It should be close to zero. When they are open, it should be about battery voltage. If not, you will never get a spark.

Thanks 4.O.T.F., my eyes must be gettin' bad, I could've sworn the points were closing all the way but 1 check w/the voltmeter proved otherwise! Don't you hate it when you beat yourself up over something as simple as that? Thanks again.

Sounds like you got your problem solved. One other thing, for those that have similar problems. With the ground cable from the battery going to the frame, and the frame acting as the current path, the old rivets in the frame build up corrosion and make high resistance connections, dropping voltage. On my '53 (6 V) it got so bad I had a special ground cable made up at the local battery store. It has two cables coming out of the battery connection. One, the short one, goes to the original frame connection. The other cable connects directly to the top bolt that holds the starter to the engine. Before my cranking voltage was about 5.2 volts. After it was about 5.9 volts.
Made a big difference in cranking speed.

Ed

Pakrat,

is your 47 an art deco or an AD?

'46IP, it's an AD, saw your pics of your 46, looks like a nice solid project.