Engine Slow/no crank question

[Phoenix827]

Hey all got a bit of a story here.
About 6 months ago I bought a 77 CJ7 with a AMC 304 that has been sitting for a while. No idea how long since it ran, but I am guessing 5 years at least. It still doesn't have a battery in it, hoping to change that this week. I changed the starter after testing it so I know that works. I tried jump starting it after I pulled the plugs and squirted some marvel mystery oil into the cylinders and let it sit a week and it seemed to crank real slowly, (but sounded ok otherwise) however, once I put the plugs back in I get nothing. it wont turn over at all.
My question is why? Is it just that I am trying to jump it from another (running) vehicle? is it asking too much of the running alternator? Could there still be enough MMO in the cylinders that it wont compress?
Thanks in advance!
Chris

 

[Manic Mechanic]

I prefer kroil over MMO. However pull the plugs and turn it over by hand using a breaker bar and I believe 15/16 socket on the crank. Spin it over completely several times before putting the plugs back in. (Great time to replace them if there of unknown age and mileage. (Make sure to mark the plug wires first)

If the motor gets stuck work it back and forth.

Keep us posted

 

[Phoenix827]

I prefer kroil over MMO. However pull the plugs and turn it over by hand using a breaker bar and I believe 15/16 socket on the crank. Spin it over completely several times before putting the plugs back in. (Great time to replace them if there of unknown age and mileage. (Make sure to mark the plug wires first)

If the motor gets stuck work it back and forth.

Keep us posted

Well, I didn't do it by hand, but I did spin it over with the starter. It seemed slow to me, but this is my first AMC 304 . Do they turn over slowly?

 

[Manic Mechanic]

No they should turn over like any other engine. Could be a weak battery, or a bad ground causing a drop in voltage

 

[CJ]

~~~. It still doesn't have a battery in it, ~~~

You have to have a GOOD and fully CHARGED battery. The battery is only thing that can produce the amperage needed to turn the engine over by the starter. Using cables without a battery won't work as your jumper system can at most, only supply a couple of hundred amps as it's Limited by the cables.