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Starter cranks fine... with ignition off...

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ersatzS2 View Drop Down
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    Posted: 01 Aug. 2021 at 4:57pm
So the fully restored to factory original #28289 is an absolute joy to drive.  I've got one persistent problem:  It cranks over pretty well when cold, and starts quickly, because, well at this point everything is brand new.  However if for any reason it doesn't start immediately, after it is hot, I find the starter won't turn over the engine.  
6V system
Battery is fine.  to test, I bought another.  no difference.

Here's the kicker:  if I keep ignition switch off, it cranks just fine.  As soon as I switch it on, it bogs and won't turn over.  

Somehow it feels like the ignition is taking too much amperage from the starter?  There is no ballast resistor although it might be built into the coil, and in any case, the ballast resistor is there to route increased amperage to the ignition, then cut out after the starter stops... 

Ideas?  I'm determined to keep the original 6V system, I've got other 6V vehicles and they crank just fine. 



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Post Options Post Options   Thanks (0) Thanks(0)   Quote 48willys Quote  Post ReplyReply Direct Link To This Post Posted: 01 Aug. 2021 at 6:14pm
Originally posted by ersatzS2 ersatzS2 wrote:


Here's the kicker:  if I keep ignition switch off, it cranks just fine.  As soon as I switch it on, it bogs and won't turn over.  

[/


My initial thought is the timing is advanced to much. With the ignition on, its firing before the piston can come to the top. I’d recheck the distributor advance weights and the overall engine timing.
1946 cj2a #28680
1948 chevy 3800 thriftmaster
1946-50's cj2a-3a farm jeep
1993 yj, aka the yj7
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TERRY Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2021 at 9:59am
Second vote for premature ignition.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2021 at 3:56pm
X3.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stev Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2021 at 4:33pm
So - starts fine when cold and is an absolute joy to drive.  When hot cranks over hard and does not want to start.  

Trying to wrap my mind around this "puzzler".


I wonder if you have a field coil in the starter that is bad.  When the engine gets hot it fails and the starter is the issue.
Stev
1946 CJ2A Trail Jeep (The Saint), 1948 CJ2A Lefty Restored
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bitz Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2021 at 11:43pm
So not that smart about motors but trying to learn. If the motor fires prematurely why does it fire when not hot.  

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Post Options Post Options   Thanks (0) Thanks(0)   Quote TERRY Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 10:48am
Remember old movies, starting hand crank cars, the advance lever and throttle were set then car cranked. Advance needed to be adjusted to prevent preignition which caused the engine to rotate backwards, kicking back the crank and breaking the "crankers" arm. Here, the preignition kicks back against the starter and it can't rotate against it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ersatzS2 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 11:08am
Thanks for noodling on this.  The advanced timing theory is interesting, but I feel like I'd see other symptoms.  It's not a question of the engine turning more slowly; the starter stops pretty much dead the instant the ignition switch is on.  So I don't think it even has the chance to rotate enough for the points to close, early or not.  

We've checked all the grounds, but I'm now wondering is there a short somewhere.  I'd suspect the starter windings, except it cranks fine with the ignition off... 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bitz Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 11:50am
Perfect.  I guess I never realized that to hand crank you adjusted the advance.  Recently watch a Brit movie from the 40s era and a few times they had to crank it over by hand. Of course they don’t show all the details 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TERRY Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 1:13pm
Look at videos on starting a model t ford. Retard advance, choke, throttle open some. As soon as it started, advance ignition. One video notes that if your model t had a starter, not retarding spark could break the Bendix gear or break teeth off the ring gear! And if hand cranked would kick back breaking arm, wrist, hand etc.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote a4cj2a77 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2021 at 1:09am
Unplug coil wire and test cranking. That would take ignition out of the equation key on or off
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ndnchf Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2021 at 9:40am
Do you have another starter that you can swap in to see if there is a difference? (or borrow off a buddy's jeep?)   That would save a lot of guess work.

BTW, where are you in VA?  I'm in Fredericksburg.


Edited by ndnchf - 04 Aug. 2021 at 9:43am
1948 CJ2A - It goes nowhere fast, but anywhere slow.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ersatzS2 Quote  Post ReplyReply Direct Link To This Post Posted: 16 Aug. 2021 at 3:46pm
ndnchf: I'm in Norfolk.  

Umm, guys... yep, timing waaaay advanced.  Reset timing and problem seems to be resolved.  Damn you guys are good. Smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ndnchf Quote  Post ReplyReply Direct Link To This Post Posted: 16 Aug. 2021 at 4:29pm
Ok.
Glad you got it figured out.
1948 CJ2A - It goes nowhere fast, but anywhere slow.
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