Crank Start On A Cj5

Can you elaborate on the relationship between the spark retard function and danger in hand cranking?

 

Traditionally vintage vehicles had a lever on the steering column to manually adjust ignition timing.

The protocol was to fully retard the timing when hand cranking. This makes the engine less likely to "kick back" (reverse rotation) before Top Dead Center when it first fires on one cylinder.

It is also vitally important to not wrap one's thumb around the crank. Keep the thumb aligned next to your fingers, and PULL - do NOT push. If the engine does kick, the crank can pull out of your grip instead of breaking your arm.

 

We had an old Allis Chalmers tractor that did not even have a place for a starter.. Cranked it by hand. The trick was to "pull up on the crank handle" with fingers and thumb on the bottom side . That way if it kicked back, you just saved broken bones...

 

This is the truth. If you're worried about a dead battery, one of those $100 lithium-ion jump start packs would be better in the toolbox than a hand crank.

 

What Pete said is 100% correct. First thing I was taught when starting all this old junk I play with is the proper way to hold a hand crank.

My Titan tractor is much different than a jeep, but the same principle applies. The worst I have had happen is I forgot to retard it once and it back fired and the crank whacked me in the chin. Luckily no damage was done. I have seen other people do similar things who weren't as lucky. Broken noses, loss of teeth, broken thumbs, ect.

 

That makes sense, thanks for the explanation. It makes you realize how dangerous mechanical equipment of that era was.
I've hand started airplane engines a bunch. That's a bit different as the natural swing of your arms pulls your hands out of the propeller arc. So, regardless of if the engine kicks back you are out of the way. The bigger danger is if the throttle is accidentally left open and the airplane runs away without or over you.

 

Here's a video demo on a CJ2A

 

Good demo.

The Titan video is very cool. I love how it fires up with one pull!

 

X2...that thing is COOL