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63 Rambler American 440

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    Posted: May/13/2021 at 4:59pm
My 63 American has our mechanics stumped and hoping someone on here might have an idea they've not thought of.  This Rambler is by far not the first vintage car they've worked on.
When I first got it, once it warmed up it would die unless you kept giving it gas.  As it is a 3 on the column this was no picnic.   Anyway, fast forward - carb has been rebuilt, timing adjusted, new plugs and wires, points worked on, vacuums checked and leaks fixed, valves adjusted, fuel filters checked etc. and it still runs rough when idling.  Any ideas?  

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Post Options Post Options   Thanks (1) Thanks(1)   Quote 1970GroceryGetter Quote  Post ReplyReply Direct Link To This Post Posted: May/13/2021 at 6:16pm
Has the fuel pressure at idle been checked?

Looks like you said Points were checked/Replaced.

Coil In good shape/tested?

Spark plugs not cracked or damaged

Same for new Wires?


They Are 100% sure they got all the vacuum leaks>? I'd replace all the lines and Tee's, as those are always cracked. 

Ground straps from Engine to chassis are present and in good shape?

Firing order did not get screwed up when had the distributor apart/wires off?

How familiar is the guy who rebuilt the Carb, with carbureutors and that particular carb?

Kind of hard to nail things down when many things changed at once....

 Back to the basics.... Fuel Air Spark. 

 Thanks! - Rudy 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MCP Quote  Post ReplyReply Direct Link To This Post Posted: May/13/2021 at 6:40pm
Thanks!  The guy who rebuilt the carb is very familiar with them. :)  Plugs and wires were replaced too.   I asked about the wires/distributor order as well.  They said it was confusing with the wires as they went according to something they found on line and it wouldn't start so they went back to the manual and at least it runs....   Thanks again for the detailed reply!!  They are persistent with it so hopefully the problem will surface soon!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: May/13/2021 at 10:46pm
Well... to be honest, if the problem really is just cold-start difficulties, and rough idle, that's about as basic car diagnostics can get, so I wonder if your mechanics are really up to the task. "Rebuilt" carb still requires the analog, subjective poking and tweaking and basic understanding of what's going on. At that level, assuming nothing's awfully broken, "all old cars are the same", in that idle and choke from 50's through 70's are more or less the same (principles anyway).

In other words it's not rocket science, except when it is -- if "vintage" means 90s, then 60s might be another planet.

If you don't have one, a factory technical service manual will be the best money you'll ever spend on the car. Here's one!


1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote MCP Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 4:57am
Thanks - yes our mechanics frequently work on 50s and 60s cars and older at times.   And a thick tech manual came with the car which they've looked at more than once from what I can gather.   the carb has been poked and prodded since being rebuilt.  Hoping for good news today.  They are scratching their heads a bit but not accustomed to giving up.  Thanks for the comments and advice!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 6:40am
If the carb seems good, check for vac leaks all around that plate it mounts on. Then look at the ignition. Even a new condensor can be bad or marginal. Also check the coil. I had a similar issue and it turned out to be a weak spark. Your mechanic probably has a spark checker where you can see the color of the spark. That could be a weak coil or just a bad/dirty connection somewhere.
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wittsend Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 11:31am
Still trying to get a handle on the specific problem.

"When I first got it, once it warmed up it would die unless you kept giving it gas."

This is typical of a vacuum leak, an idle adjustment set too low and/or the idle mixture set too lean.

"Anyway, fast forward - carb has been rebuilt, timing adjusted, new plugs and wires, points worked on, vacuums checked and leaks fixed, valves adjusted, fuel filters checked etc. and it still runs rough when idling."

Having repaired/replaced all the mentioned items have they used a vacuum gage to check for characteristics of burnt valves (which will make for a rough idle). Have they done a compression check? How does the car run otherwise? Once underway does it run well?
'63 American Hardtop
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MCP Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 12:42pm
They believe there was a problem with the choke - something with the bushing(s) which indeed did mean a leak - they hope to have it fixed very soon and we'll then know if it takes care of the problem.  Had to send out for that repair.  Otherwise I believe it was running well when moving.    As our mechanic said to me this morning - "we are more stubborn than the car."   
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