Your donations help keep this valuable resource free and growing. Thank you.
|
196 Dieseling, now no-start |
Post Reply |
Author | |
tungsten
AMC Apprentice Joined: Mar/09/2017 Location: Chicago, IL Status: Offline Points: 33 |
Post Options
Thanks(0)
Posted: Jan/22/2022 at 11:15am |
My ‘63 550 has had a high-idle issue, causing dieseling, lately but yesterday was the worst it had ever been. Which led immediately into a no-start condition.
Before I start worrying about cracked blocks and heads, where should I start diagnosis? The engine almost catches, but it feels like it may have jumped time. Is that even possible? |
|
ramblinrev
Moderator Group Joined: Dec/28/2008 Location: Wisconsin Status: Offline Points: 11543 |
Post Options
Thanks(0)
|
It could have jumped time, but with steel timing gears/chain (as opposed to nylon gears which were common in the later 60's and 70's), it's not real likely. Research how to find Top Dead Center on cylinder 1. Find out if the distributor rotor is in line with number 1 terminal on the cap and wire. And then see if the timing mark on the vibration dampener lines up. Do you know how to use a timing light? Also, check point gap, as point gap and functionality also impacts timing. Make sure the 'rub' block on the point set didn't fall off or wear out. If you had high idle, and then dieseling, you also had a bunch of raw gas going into the cylinders. So it could just be flooded, and plugs could be fouled. Dieseling is partly a carburetor issue, and partly a function of how much carbon has built up in the cylinders (to produce a hot spot for ignition.)
|
|
74 Hornet Hatchback X twins (since 1977)
62 American Convertible (still worth the $50 I spent in 1973!) AMCRC #513, AMO #384 70 AMX 360 4-speed (since 1981) |
|
purple72Gremlin
AMC Addicted Charter Member Joined: Jul/01/2007 Location: Illinois Status: Offline Points: 16614 |
Post Options
Thanks(0)
|
Almost catches? Could be a bad condenser. But you need to fix the dieseling and I bet if you fix the high idle.... it will fix everything else
|
|
Heavy 488
AMC Addicted Joined: Apr/27/2019 Location: In the Status: Offline Points: 3557 |
Post Options
Thanks(0)
|
High idle Doees the choke butterfly operate? Is the fast idle cam stuck?
|
|
pacerman
Supporter of TheAMCForum Joined: Jul/03/2007 Location: United States Status: Offline Points: 9060 |
Post Options
Thanks(0)
|
You need to keep the air out of the engine to stop the dieseling. Make sure the throttle plate goes all the way to the idle setting when you let off the gas. Look for vacuum leaks. If your old carb has high mileage the throttle shaft bushings could be work allowing a vacuum leak through the base of the carb. Joe
|
|
Happiness is making something out of nothing.
|
|
tungsten
AMC Apprentice Joined: Mar/09/2017 Location: Chicago, IL Status: Offline Points: 33 |
Post Options
Thanks(0)
|
Good news! It was just flooded. I pulled the plugs to let the chambers evaporate and she just fired right up.
Now onto the idle issue…
|
|
wittsend
AMC Nut Joined: Apr/15/2020 Location: California Status: Offline Points: 430 |
Post Options
Thanks(0)
|
Your high idle is likely a misadjusted carburetor choke. As mentioned when the car is cold and the choke active there is a stepped piece of linkage that increases the idle speed. As the carburetor warms up the choke begins opening up and the idle drops into lesser steps to lower the idle speed. Eventually the steps move to a point they are no longer active and the main idle adjustment becomes the active setting once the car is at normal temperature.
If the choke is misadjusted it may be remaining on one of the steps creating both a high idle AND a rich condition that can cause the car to diesel when the ignition is turned off. A too high float adjustment can also contribute to dieseling because gas is splashing into the carburetor.
|
|
'63 American Hardtop
|
|
tomj
AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7555 |
Post Options
Thanks(0)
|
What's this car and engine's history? Recent find? Daily driver? Restoration?
Is the carb a sticky smelly mess? Recently rebuilt engine? Old survivor? First Principles is the way to go. Everyone's advice here is in line with that. Make sure basic timing is close enough. If that's OK or close, I smell carb issues. high idle? Do you have a vacuum leak? Ported vacuum to the distributor? |
|
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com |
|
tungsten
AMC Apprentice Joined: Mar/09/2017 Location: Chicago, IL Status: Offline Points: 33 |
Post Options
Thanks(0)
|
It's a survivor that I'm trying to put more into daily service. Picked up from Bring a Trailer a couple years ago, previously owned (and written about by!) automotive journalist Jamie Kitman, given a once-over and some general repairs by Frank. I've put a Daytona rebuild kit into the carb, the engine has been lightly rebuilt, and all of the ignition components are up to par. I suspect the engine builder just cranked up the idle stop screw to fix an issue with a deceleration stall, before the really high idle it was getting stuck on fast cam pretty often when coming to a stop. I also think my throttle linkage is binding up in a more open position. I think I'm going to lube all of the joints there first. Tom, you're my literal hero in dailying these beasts! My household is downsizing fleet size, and as the only working member who's commute is both very short, and also served by reliable bus service, I've drawn Rambler duty.
|
|
tomj
AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7555 |
Post Options
Thanks(0)
|
Well thanks! Divide and conquer helps. IT's too easy to get distracted by a dozen (or only three) problems. If the throttle linkage is AFU, then disconnect it. You don't need it to get the curbside basics right.
YOu might find that when you get the carb untangled, the ignition might not be as perfect as you thought. It doesn't mean you're a bad person, lol. You'll both get better at it, notice more, and unmask subtler problems with incremental fixes. And you'll discover why the EPA demanded 100,000 mile tuneups from new cars. This stuff can get really subtle; and paying by the hour, the tendency was to fix things "good enough" to get to work, etc. Today with a 50, 60 year old car, your focus is probably different. I spend the time to unsort this crap because 90% of the time I actually enjoy it, lol, and can spend the time thinking and working in ways I could I couldn't 40 years ago. You wanted adventure, you got it. Didn't? Too late now! lol My millennial neighbor recently bought a nicely done 32 Ford. He has no idea what a carburetor does, at all. He was driving with the choke on all the time. There's only two adjustments (Zenith 2) and both were of course fouled up because the choke was on. He's very smart -- but this is all alien tech, no one around him has any (^&*)&()*( idea what anything like this is -- but he's persisting and figuring it out. He's worked out the crashbox (no synchros) just fine. We all don't know something. |
|
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com |
|
Post Reply | |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |