I need some advice on how to fix this problem with rough running

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avent40
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I need some advice on how to fix this problem with rough running

Post by avent40 » Sat Sep 21, 2019 8:55 pm

I cleaned the fouled plugs and put in the new coil and she started right up. This morning I started it and was able to drive it in first gear ok, but when i changed to the second gear, it started backfiring and the started clunking out and had to drive in first gear to and from the car show today. I took the carbuerator bowl off and cleaned and sprayed card cleaner to see if the float was stuck and everything was ok. I took the timer cover off and cleaned the cover and oiled it and still she hard starting and white smoke is coming out of the carb, do you have suggestions what it could be and what to do? 


Norman Kling
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Re: I need some advice on how to fix this problem with rough running

Post by Norman Kling » Sat Sep 21, 2019 9:05 pm

White smoke is usually an indication of water in the cylinders. Black smoke is from rich mixture, and blue smoke is from oil burning. Have you done a compression test? You should have about 55 lbs pressure at sea level, a bit lower at higher elevations, but all 4 cylinders should have approximately the same compression. If you have one or two low, especially if they are adjacent cylinders, you could have a bad head gasket. That would cause the engine to miss and hard starting. You could also have too advanced spark. An advanced spark would run better at higher speed, but run rough at slow speed. This would cause it to run better at high rpm such as in low gear, but rough at slower rpm, especially when pulling right after shifting to high. Anyway, try testing these two things and see what you find.
Norm

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Bill Robinson
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Re: I need some advice on how to fix this problem with rough running

Post by Bill Robinson » Sat Sep 21, 2019 9:09 pm

How long has the gas been in your tank or cans? Longer than 3 months? To me, it sounds like a sticking valve(s), most likely caused ethanol gas deposits. I've had the same problem and my cure (thanks to advice on this forum) was to remove the spark plugs, pour approx. 1 tablespoon of Marvel Mystery Oil in each spark plug hole. Then with the key OFF, hand crank the motor slowly a few turns, then let the engine set- overnight if possible, after replacing the plugs. After the rest start the motor til the smoke clears. If the popping and rough running stops, the drain the old gas and replace with new.

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Charlie B in N.J.
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Re: I need some advice on how to fix this problem with rough running

Post by Charlie B in N.J. » Sat Sep 21, 2019 10:16 pm

fouled plugs. from what ? oil or a very rich mixture ? what is the plug gap ? a compression test might be in order to eliminate the possibility of oil fouing but first what is you carb needle set at ? 1 1/2 turns is the normal starting out setting with adjustments done later when warm. will foul plugs if too rich. white smoke from the carburetor ? is it puffing back through the carb or did you print that wrong ?
Forget everything you thought you knew.


Wayne Sheldon
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Re: I need some advice on how to fix this problem with rough running

Post by Wayne Sheldon » Sun Sep 22, 2019 2:20 am

You replaced one coil? What is the condition of all the coils? Properly rebuilt? Somewhat worked over? New capacitors? Why was the one coil replaced?
If one coil is significantly different that the other three, the dwell time could be way short and one coil could be firing early causing a partial kick-back while running and make a T run horribly. Or the one may be firing a bit late, will run poorly, but not horribly.

However, I too am more suspicious of the whitish smoke. Likely a head gasket issue as others have said.

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Kaiser
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Re: I need some advice on how to fix this problem with rough running

Post by Kaiser » Mon Sep 23, 2019 7:00 am

I read white smoke coming from the carbs, that is probably from coughing back through the carbs, which points in the direction of running too lean, which explains the lack of power in high and the rough running.
I suggest checking the inlet manifold for leaks, easy way is start the car and while it is running spray some brake cleaner or WD40 or something around where the manifold meets the cylinderblock, if the motor smooths out or shows a rise in revs you have a leak at the gaskets .
simple test, performed in minutes.
If this shows no leak, you have to check fuel flow to carb, float level, float needle, (viton tipped needle can be a problem)
When in trouble, do not fear, blame the second engineer ! 8-)
Leo van Stirum, Netherlands
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RustyFords
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Re: I need some advice on how to fix this problem with rough running

Post by RustyFords » Mon Sep 23, 2019 7:27 am

Kaiser wrote:
Mon Sep 23, 2019 7:00 am
I suggest checking the inlet manifold for leaks, easy way is start the car and while it is running spray some brake cleaner or WD40 or something around where the manifold meets the cylinderblock,
If you use brake cleaner, use the non-chlorinated version. When the chlorinated version hits a hot manifold, chlorine gas is released and will damn near knock you out if you're in a garage. Ask me how I know.
1924 Touring

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