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Optima battery suddenly too weak to crank on 48 DeSoto!


MarcDeSoto

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Tell us about the engine overhaul. You've stated it was rebuilt 30+ years ago.....what did this overhaul involve? Did you do the work or was it farmed out? How has the engine been stored for the past thirty years?

 

Also, throttle tip-in stumble could also be due to the distributor advance not working properly.

Edited by Sam Buchanan
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5 hours ago, LeRoy said:

Like NASCAR!

I was just thinking this thread started 7 pages ago with a dead battery  :D

 

@MarcDeSoto One thing I'm not clear on .... Is your cooling system operational? Can you let the engine get up to operating temperature & run for awhile?

 

I have no experience with starting up a old school rebuild. I know modern rings will seal almost immediately.

While I think older cast iron rings  will need some time to seat. 

 

I think it is good to get the bugs worked out & know it runs.

Now If it was my rebuilt engine, I would next want to start it & run it for 45 miniutes-1 hour?

Give it time to heat up, gaskets, seals,rings to get set in place.

I would try to avoid a bunch of 2 or 5 minute runs before the engine has had time to get settled in.

 

The poor acceleration sounds like a bad accelerator pump.

Or it could be the rings are not set, you are a little low on compression, burning some oil .... Too early to troubleshoot yet.

 

Is even better if you can take the car out & drive it to break in the engine proper.

At least get a cooling system working on it and let it go through some heat cycles before troubleshooting little issues.

 

My 2 cents.

 

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1 hour ago, Los_Control said:

 

 

Is even better if you can take the car out & drive it to break in the engine proper.

 

 

Driving this car now is going to be kinda breezy!!  ?

Edited by Sam Buchanan
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I always try to follow Los Controls advice.  I seriously thought about taking it out for a drive around town.  Who needs the body anyway?  I could stand on the frame rails and work the pedals one foot at a time.  I wonder what a cop would do if I drove by him.  Howdy officer, just breaking in my 48 DeSoto.  I'll put the body on later.  I'm thinking of putting some anti rust coolant flush in the radiator and then flushing the system after running it awhile.  What's a good product?  

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On 1/18/2023 at 4:59 AM, LeRoy said:

I find that the squirt needs to pretty robust.

 

My thought process would be something like this:

 

-With the engine not running does the stream spray against the opposite side of the throat and splash, even to the point of a little coming out the top of the carb? 

-Does the stream of gas start as soon as you move the throttle or is there a slight delay? The spring under the pump too strong? Spring on top too weak?

-Is the leather good and soaked in fuel, I've even smeared a little light grease on the raw side of the leather a few days before assembly to ensure its fat and fluffy.

-Is the acc pump body real smooth? I make a little reamer out of fine sandpaper and a piece of dowel mounted in a drill and hone the inside of the pump cylinder. Don't go wild just smooth things up a little.

-Are the little passages from the pump to the throat completely clean? I think the last one I cleaned up had 3 little passages that come into the throat, only 1 was passing fuel initially. Run lots of brake cleaner then compressed air through them.

-Are the jet and check ball in the bottom of the pump operating properly? If you mixed up the accelerator jet and the power valve jet you get a puny stream and a stumble off idle. The power valve gets the jet where the center poky (please excuse the use of techy lingo) sticks proud of the jet, the acc jet's poky thing is down inside the jet. 

Are you leaking a ton of air around the throttle shaft? If your shaft is loose you can kinda tune this out with the idle air needle while at idle but it causes a little stumble just off idle if its real leaky. 

 

That's a lotta ramble and may not even be related to your problem. Keep in mind that I don't know what I'm doing and you should take my advice with the appropriate caution.

 

(I ignored the smoke for the first 30/45 min of run time, lots of stuff to burn out)

I am just reading this again closely and it is really good advice.  I'm going to follow it as I troubleshoot my hard starting problem!  Thanks, LeRoy!  Marc.

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6 hours ago, MarcDeSoto said:

I always try to follow Los Controls advice.  I seriously thought about taking it out for a drive around town.  Who needs the body anyway?  I could stand on the frame rails and work the pedals one foot at a time.  I wonder what a cop would do if I drove by him.  Howdy officer, just breaking in my 48 DeSoto.  I'll put the body on later.  I'm thinking of putting some anti rust coolant flush in the radiator and then flushing the system after running it awhile.  What's a good product?  

 

Sounds perfectly normal to me… ?

 

hp1140196.jpg.76253f11f2bef0f6e2cb9af134f4d345.jpg

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15 hours ago, MarcDeSoto said:

I'd like to get the name of your upholstery guy!  He did a great job and love the creative approach to the bucket seat!  

I'd bet it came stock with a bench seat, buckets won't look right in that cab at all.

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? That Bucket Seat did the trick, but it also added a bit of a hazard. My carb wasn't tuned correctly yet at that point and it had a nasty hesitation when opening the throttle. It would bog for a second then take off suddenly causing me, and the bucket, to rock back. (accelerator pump jet was plugged) If it wasn't for the rigid steering column and wheel to hold on to I'd have probably fallen over backwards and got myself run over. 

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