The Stovebolt Site Forums The Shop Area Engine Shop starts when cold but not when it is hot

HI
I have two problems

1. I recently purchased a 1951 chevy styleline special. with a stovebolt 216 engine and 3 speed column shift. The car starts fine when it is cold and it runs without stalling. but once i turn it off i cannot start it back up again. It cranks fun just doesnt catch.
2. while the car is running it has a lot of vibration. i have already replaced all the spark plugs on it and it does not help . and tuned up the engine.

Chaimv,

Welcome to the Stovebolt. Many Canadians are kicking around here so you shouldn't feel lonely.

Finding your vibration might take some sort of special tools. A compression check with a gauge would be a good starting point.

I am thinking your vibration might actually be a 'shaking' from a cylinder that isn't firing properly.

If you get a chance, next time it does the vibrating thing, pull each plug wire, one at a time. Most should make a big difference when removed..if one doesn't make a big difference, you might have found the culprit.

If this vibration is actually a shaking of the engine, this miss could also be caused by faulty plug wires, bad distributor cap, or a valve malfunction.

If your car turns over nicely when warm, but won't start, it could be a fuel issue.

Sometimes a carburetor will percolate fuel into the intake after the engine is shut off. This can flood the rig and make it hard to start. Black smoke out the pipe on start up would be a clue.

There are many things to look at for a sure cure. The comment on the vibration could be something entirely different than I indicated.

I called it a shaking of the motor, you might mean a subtle vibration. This would be different.

Other folks will soon be along with more ideas.


Stuart

Thanks for the advice

I will try pulling the spark plug wires to see what happens. and ocasionally there is puff of black smoke while the car is running. You mentioned that it might be something with the carburator. is there nay way to check or repair it without doing a full rebuild of the carb

Do you have a Rochester Model B Carb. Not too much to adjust. Get the rebuild kit and follow the directions, they are very simple. If it is flooding out it could be your float height or the shut off. Depending on when the carb was last service you may need to replace a few gaskets. Good luck.

the car is all origional. it was in indoor storage for the past 20 years. and i am pretty sure that no-one has ever adjusted anything on it. i will try getting it reuilt and i will let you guys know what happens

Thanks alot

chaimv,

I think the only sensible way to approach one of these old carburetors is a tear down, bath and a rebuild.

There are only a few external adjustments, and they most likely wouldn't address your problem.

The rebuild kits are inexpensive and the skill level required for the rebuild is only moderate.

Keep in mind the carburetor has not been deemed public enemy #1 yet.

With these kinds of problems, the SOP is to do a tune up and replace as many of the 'wear items' as you can.

The car is over 50 years old and probably needs some TLC. Instead of finding a specific item that is at fault, it is more expeditious to tune it up, then see what doesn't work!

If you could analyze the problem in finer detail, the search would be narrowed. Good luck


Stuart

I already did a partial tune up.
i did a valve adjustment, cleaned the fuel pump and fuel tank from all the rust, cleaned the air filter and replaced all the spark plugs. so i guess im just going down the list of things that have to be done. I guess ill go order a rebuild kit and give that a shot and ill let you know how it goes

I had this same problem on my 47 pickup and it was a bad coil that caused this problem. Hope you get it sorted out.

I had a problem with my 38 not wanting to start warm. Making sure the carb was fully up to snuff helped but the big improvement was putting a Optima Red Top 6V battery in it. Most 6V batteries have 400-500CCA where the Optima has 800CCA. BIG difference in cranking speed. Also make sure your battery ground is good and that you have no smaller than 1 gage battery cables. 0 would be better. You can get them at a farm store usually. Most parts stores sell 4 gage. 6V starters pull a LOT of amps.

chaimv,

When you did the valve adjustment, did you do it cold or hot, and what settings did you use.

Don't forget plug wires...they can leak just like an old garden hose!

Stuart

Back again

I did some work on the car over the last few days. still no luck

i cleaned and rebuilt the carb, with a rebuild kit i got from Napa
I changded my battery for a 625 CCA

I checked to make sure all the spark plug wires are good and are not misfiring.

the car still starts well when it is cold, however once it gets warm one of two things happen when i try starting it

1. it cranks and does not start like i mentioned in the orgional post or the engine fires up for about 2 seconds and dies.

Please help.

i already ordered a fuel pump rebuild kit, as well as a new coil, distributr cap and rotor.

please let me know if you have any suggestiosn

Thanks

my chevy used to do that it was the timming the best way is to do it by ear and also make sure its not running on choke
derek

Hi Caimv!

I like to change everything in the ignition when I try to troubleshoot stuff like this.

(e.g. Plugs, wires, cap, rotor, condenser, points, rotor)

A new coil won't hurt anything either. It should rule that out as a problem.

Let us know how things go when you've got that distributor cap and rotor on!

chaimv,

Good to have you back..sorry the problem isn't solved.

You sure have done a lot. I am about out of suggestions. The fact that it will sometimes start and run for a few seconds sure sounds like a fuel/carburetor problem.

Next time you drive it, and it's warm and ready not to cooperate, I wonder if you could 'prove' the carburetor theory.

Manually dump a small amount of fuel down the carburetor and give it a try. If it starts, this will be a clue.

Saskwolf (Canadian too) mentioned the hot coil syndrome...this could also do it.

After you get your new parts installed, give it another try and let us know. Good luck.

Stuart

Check you heat riser is it stuck closed? You could be perculating your fuel.
When the engine vibrates, do you loose power?
The vibration you refer to could be just that, a vibration, usual cause a bad engine support.

May be vapor lock.
Try wooden clothes pins on the gas line.


Thanks, Kelly

53 3100
http://www.cravy.com/53-3100/LadyAfterRats.jpg

Try this link:

http://www.thecarburetorshop.com/Troubleshooting.htm#Hardstarthot

Jon.

Hi everyone

some people have emtnioned that it mught be a timing issue. i was wondering if you can give me some pointers on how to set the timing

chaimv,

Your rig is running, so you only need to check, or fine tune the timing.

The best way to approach this is with a timing light. If you don't have one, maybe a friend does, or a rental yard might.

The light is attached to the battery, and the pickup is hooked #1 plug wire.

The timing mark on these engines is usually a ball embedded in the flywheel. It is located in a viewing hole above the starter

A small pointer, looks like a nail, hangs down in the access hole, and when properly timed, the steel ball and pointer will line up....frozen in time by the strobe of the timing light.

Rotating the distributor will make the ball parade forward or backward. This is called BTDC or ATDC...before top dead center or after top dead center.

What you are seeing, is when the plug fires, in
relationship to where the piston is in the cylinder.

These are the highlights. More people might pop in with details I have missed.

Stuart

You have to figure out if the problem is fuel or ignition. Make the truck warm and when it won't start pull the fuel line to the carburetor and crank the starter while observing if fuel squirts out. Stop as soon as you are sure and be careful with this (fire extinguisher at hand). If you are getting fuel then check for spark at the points. Take the distributor cap off and turn on the ignition key inside the truck. Manually turn the engine until the points open. You should see a spark between the points. You can rock the engine back and forth a bit. You should see a spark when the points open. If you are getting fuel at the carburetor and spark at the distributor then the truck should start. At least you will have eliminated a lot of possibilities.

Hi guys.

i set the timing of the engine. I used the instructions from the chevy shop manual as well some of the pinters that were mentioned here. I set the fly wheel to 5 degrees before the mark and i set the distributor to half way before firing cylinder #1.

Now my engine does not fire up, it cranks but does not fire up, i have checked to make sure that the dsitributor pruduces a spark and it does and there is a smell of fuel while the engine is cranking.

any ideas

my truck used to do that make sure the choke is open and the timing is right and set the points /dwell

chaimv,

The conventional procedure to time the engine would require it to be running. Your car ran..now it doesn't.

The procedure you describe above looks more like a static timing procedure.

Your engine would start, so a timing light would have been the order of the day to fine tune that timing.

You obviously need to get back to square one and get the engine running again. Read the Tech-Tips section on this forum, there might be a clear outline on how to time your engine with a light.

Stuart

unfortunately i do not have a timing light. however as you said i need to get back to square one and to get the engine runnning again.
any ideas on how to do that?

chaimv,

When you did your timing procedure outlined above, it appears you only moved the distributor by hand...you didn't remove it or change wire position in the cap.

If this is the case, merely have a friend attempt to start the car as you slowly rotate the distributor by hand. It should start, and moving it slightly should either improve the idle speed or make it worse.

Rotate the distributor until the car runs the smoothest at an idle and lock it down.

Now that it can run, it's time to find a timing light and do the procedure again, but with some "technology". Good luck.

Stuart

Unfortunately i think that i did more damge then realized. i did change the wiring on the distibutor cap and i put it in the following firing order 1,5,3,6,2,4. also call me stupid but i did remove the distributor from the engine based on a mechanics advice and as i said when i put it back i made sure that the rotor was half way to cylinder 1. i set the wiring only after the distributor was bolted to the engine again. there is another problem. I cannot turn the distributor too much because of the vacuum advance. i dont know if it is a steel pipe on all cars or just mine so the amount that i can turn it is minimal. some people that i talked to mentioned that i should change it to a rubber hose to have more movement.

chaimv,

No damage was done. It is just more difficult now to get back to the beginning.

The copper tube is fine. When everything is adjusted properly, there is plenty of flex in that line for the minimal movement the distributor needs.

I would suggest you use the 'search' icon on the top of the page and look for "how to time engine", or even the Tech-Tip section.

If you can't find the procedure, come back and fire away hear. It sounds like you are getting some input from a mechanic/friend...help is great, but it needs to be accurate too.


Stuart

hi guys

i have a carb problem. After the rebuild i set the timing and the car did fire up but ran very rough. That is not the carb problem. teh actual problem that i have is that teh carb is leeking from the throttle linkage are. What i mean is when ever i press the gas pedal some fuel leaks out from the little shaft that teh trhottle linkage is connected to. i have disassembled the carb to try to figure out where it is leaking from. and it looks like it is leaking from the little plunger next to the fuel basin. the problem is i have no idea how fuel is getting there and maybe it normal. i have not checked to see if it leaks while the car is running. i have only checked when the car is off.

Thanks
chaimv