engine turn over

68 M715 230 stock, New batteries month old. I go to start it and with in 10 seconds truck sounds dead. Not firing I don't understand the points and what they do. I'm thinking I have some kind of spark issue. Changed the rear main last weekend. Drove it yesterday ran and started fine. Batteries were showing 10.8 and 12.9 volts after driving it for a few hours, they evened out after I shut it off to 12.4. The ? is why are the batteries so off voltage wise. the 10.8 one was closest to the kill switch. Need some advice or expertise.

because of the various ways people talk about auto problems, please be as accurate and consistent as possible.

Distance from kill switch doesn't matter.

What does, "sounds dead" mean?

If you mean it wont crank or is cranking slow, then that has nothing to do with firing.

10 seconds is way to quick to kill even one good battery. So if its not cranking you need to figure out your electrical problem first.

"Changed the rear main", the rear main seal? That has nothing to do with a truck not starting.

A 10.8v battery is dead, a good one should be in the 12v range. A charging system will run in the 13v range, sometimes 14v. So after a drive the batteries may show a high voltage and then drop down a little. However if you have one that is 12.9 and one 10.8, the lower one will run the higher one down. If the lower one is actually bad, replace it. Even new batteries can be bad, put a load tester on them.

This is a good one.

http://www.amazon.com/3181-Heavy-Dut...ry+load+tester

or take them to auto zone.

What I find odd about what you say is, "they evened out........to 12.4". Its a 24v system, so how did they even out to 12.4? You were testing them individually, the 10.8 and the 12.9, but when you hooked them back up you should have been in the 24v range.

Do you have the batteries hooked up to give you 24V? Are you drawing 12v off of one of them for any reason?

Make sure all of your connections are clean and tight. Clean and tight means clean and tight. Dirty and loose connections account for the majority of battery problems.

12.6 volts is a fully charged battery at rest. Anything lower and it needs a charge.

14.4 volts is what should be seen while the truck is running with a good alternator.

That is per battery.

If you still have everything 24 volts, you should have 25.2 across both at rest and 28.8 with the engine running.

The points open and close to ground the coil. This causes the coil to send high voltage to the cap which then sends it to the spark plug. The technical term is collapsing the coil charge. Anyway, how long the contacts touch each other and how long they are open all play a part in how the engine runs. Since you can't adjust the points with the engine running as most muscle cars could do. Open up the -20 manual and follow the steps exactly to set the gap/dwell.

Thanks Barr Man! I pulled a spark plug to check for spark. I am getting a dull white with some orange in the spark. I appreciate the advise and am looking at the manual for the points.

Glad to help. Look into testing the coil because that is the leading cause of these things not starting. Bad coil.

Where exactly in Indiana are you?

Warsaw between fortwayne and southbend

I went to high school in Kendallville is why I ask.

Check your coil and read all the multiple threads about the good, the bad and the ugly replacements available these days before you buy one.

If we were still running steel back up here on back loads, I was picking it up in Columbia City at the steel mill there...

Barrman is an expert...no question...and he is dea on about the coil being THE #1 issue with starting problems...I will add this though as it is probably the #1 for overall electrical issues, make sure the ground from the batteries is making a GOOD ground to the frame...take the cable off the frame, clean the wire and and the frame where it mounts like crazy, use a toothed lockwasher to dig into the frame metal when reassembling and, I like to anyway, coat the ground wire end and the frame with a light layer of grease to help prevent any future corrosion.

Military vehicles are KNOWN for bad issues with grounds...

The truck stop in Columbia City has a chili cheeseburger meal that is great. I was thinking about that meal the other day and I haven't been there in almost 30 years.

Jon brings up a good point about the ground connection. The little star burst shaped washers are a must to allow metal to metal contact. Don't substitute something else. Use the starburst washer.

Slept there several times last winter....