'52 Plymouth, hard starting

[52ismine]

This problem has been happening since I got the car.

 

Turn the key and crank, crank, crank, and not a pop. Pumping the gas pedal doesn't help. A quick short squirt of starting fluid down the carburetor and instantly, and I mean instantly, it fires right off and runs. Does this if has been sitting for a few hours or longer. Tighten all the fuel connections, and after cranking if I undo the fuel line at the carburetor gas comes out so I think I am getting gas at the carburetor. Newer (or at least not a lot of miles on them) points, plugs, wires, etc... and the timing was checked. Thought maybe the coil was hooked up backward but that checked out. Carburetor was rebuilt right before I bought the car and all fittings on that are tight.  Thought maybe there might not be enough vacuum to pull the air through the carburetor but compression is 85-95 across the cylinders and no smoke or oil usage. Other than this problem there are no other problems.

 

Thoughts on what to do/check next?

 

 

[Bryan G]

Shine your flashlight down the throat of the carburetor while working the throttle. Make sure you see some gas squirting; if not, your accelerator pump needs attention.

[keithb7]

Sure sounds like a fuel supply problem. Start with some diagnostic testing.  What is fuel pressure at carb inlet? Put a vacuum gauge on intake manifold port. Check vacuum as adjustments are made. Is carb responding to A/F adjustments, effecting vacuum readings. 
 

Who rebuilt the carb? How thorough of a job was done? Ultrasonic cleaning? Could be a jet problem. Could also be an acceleration pump problem. If you put some raw gasoline in the carb, not starting fluid, will it start?  Suggest you do not use any starting fluid. Its hard on piston rings and cylinder walls. 

[Plymouthy Adams]

check that your Sissons choke is working and that you are in fact SETTING it proper when starting....it is NOT automatic to the sense of the later chokes, you have to depress the pedal with starter engage as this is when and where it gets it power and then let up on the pedal for the choke to set....

[OUTFXD]

Check the Holy Trinity,  Fire Water & Air.     Make sure you are getting spark(Test at Spark plug),   Makes sure you are getting Fuel (test at carburetor),  Make sure your are getting air (Air filter... as easy as that).   Once you have all three you can begin checking voltage (Is your generator/ alternator Putting out) Timing.   Check the fuel filter and fuel pump. etc etc etc.   Hopefully the tests above will direct you twords the issue so you can sort it out!

[52ismine]

Manual choke.

 

I have used a splash of gas to start it (when the starting fluid can was out of propellant) but prefer not to due to safety issues.

 

Put a pop bottle over the open end of the fuel line at the carburetor and cranked it over a few times. Gas was in the bottle, don't know the pressure. 

 

Has spark. 

 

Even though the carb was rebuilt shortly before I got the car, in messing around with the linkage it seems "loose", as it moves side to side in the carburetor base. Could a worn shaft be enough of a vacuum leak to cause this issue?

[Dartgame]

Had a similar issue with my 52. Had plenty of spark, was getting gas into carb. Turned out to be old deteriorated gas, dumped the tank, and carb put in fresh gas and it started and runs fine. Remember these motors are low compression, they wont tolerate old gas. I suspect the higher volatile components in gas evaporates over time and you are left with a kerosene like fuel.

[52ismine]

On 5/18/2023 at 3:53 PM, Dartgame said:

Had a similar issue with my 52. Had plenty of spark, was getting gas into carb. Turned out to be old deteriorated gas, dumped the tank, and carb put in fresh gas and it started and runs fine. Remember these motors are low compression, they wont tolerate old gas. I suspect the higher volatile components in gas evaporates over time and you are left with a kerosene like fuel.

That could be a possibility but this problem has been going on for awhile and I will, at a minimum, go through a tank of gas a year. Not that I run it dry and refill so I guess there is always some "old" gas in there at any given time. 

 

I could always run the tank low and drain what is left and start with all fresh gas.

[52ismine]

Problem solved!

 

Knew I had gas. Obviously had air. Only think left was spark.

 

Previously tested the spark by a helper holding the sparkplug to the block while I cranked it over and him confirming I had spark. Quality of spark I didn't question. It has a Pertronix unit on it and in reading through the trouble shooting guide one of the causes of a no start is resistance in the ignition wire and it explained how to "jump' the wire to test for this. Followed the directions for jumping it and it fired right off. 

 

Disconnected and cleaned all the connections from the battery to the solenoid to the horn relay, etc. Everything was tight and looked clean while taking it apart but after hooking everything back up it started right away with the turn of the key. 

 

So some minor corrosion somewhere was preventing preventing a good spark and the starting fluid (or gas) would provide enough in the cylinder to get it to start with the weak spark.

 

Tried to start it with a hot engine, no problem. Starting after it has sat for a few days, no problem. Hopefully problem solved. Sadly after all these years of frustration it was caused by a simple problem.

[OUTFXD]

Congratulations!  Now get out there and enjoy you car!

[keithb7]

Glad you found it.

 

Unfortunately, 1 more ill-fated Pertronix story to add to the pile.

[52ismine]

1 hour ago, keithb7 said:

 

Unfortunately, 1 more ill-fated Pertronix story to add to the pile.

 

Not an issue with the Pertronix unit. The issue was with some corrosion in the electrical circuit. Same thing could be said if the points where corroded/burnt, bad connection to the coil, rotor or distributer cap worn out. 

[Go Fleiter]

strange to me, Keith, that You have so many bad experiences with Pertronix!

As suitable for my P23, I use a 6V minus grounded unit since 2007 and 25 000 mls without any problem.

I can recommend it strongly, if not the originality is first - but the driving!

The original setup failed constantly because of inferior quality of the point contacts.

I even have a spare unit in the trunk.

 

Above all, since 23 years starter motor, ignition coil and (since using it,) the pertronix too gets 12 V from two 6V batteries in series while starting.

I never tried how much Voltage the 6V Pertronix would stand, but liberately estimated, I didn´t want to go over 8V.

So, again while starting, a V limitation circuit keeps the Pertronix at 8V. Yes, and a spare circuit is on board too...

 

I never needed the spare units, but other users seem not to have such luck.

 

btw.: my car is not presented to be judged for originality, I just drive it for the fun.

And I love not to be blocked by trivialities of old technology

 

Greetings from Düsseldorf!

Go

 

Edited May 28, 2023 by Go Fleiter