Starting problems

[Thin Lizzy 37]

Hi All,

Hoping you can help me please.  Every time I go to start my 69 it takes 2-3 minutes to start and usually have to turn the key about 20-25 times.  The engine turns over but doesn't start.  I put my foot on the pedal to get some gas into the carb, but still doesn't work until a minute or two later.  Not sure what's going on.

It's a 351w 4 barrel.  The battery is fully charged, it has a Pertronix Ignitor and Flame Thrower fitted and it has a relatively new edelbrock carb fitted.

The car seems to run fine when I get it going, though a little down on power.  Do you think the plugs need replacing?  Or it is something else?

Any help would be gladly appreciated.

Thanks,

Mark.

http://www.fordmustangmach1.com

[1969_Mach1 333]

Could be a couple of things.  Fuel in the carb is percolating and flooding the motor.  Edelbrock carbs have a history of issues like percolating and vapor lock due to heat.  More so when on an aluminum intake manifold that has the heat crossover passage open.  No spark condition is another possible option.  You'd have to quickly check for spark at a spark plug when the motor won't start.

If you believe the spark is okay I would first try a phenolic carb spacer to help insulate the carb from heat.  Use the 4-hole type if you have a stock intake or aftermarket dual plane intake manifold.

[Midlife 814]

Does this happen both when the engine is cold and after it has warmed up? 

Before starting, take the air cleaner off and look down the carb as you move the gas lever: you see gas squirting down? 

If only cold, does the choke get set?  Can you manually set the choke using the accelerator linkage?  Do you even have a choke?  Or is it electric? 

[barnett468 418]

I for one wouldn't buy a carb spacer until it is determined that you might need one. I have probably had over 50 cars with edelbrocks with no spacers and they all started fine after I tuned them.

1. Has it always done this? If not, exactly when did it start doing this?

2. does the engine turn over noticeably slower after it is at operating temp?

3. If you have a numerical temp gauge, how hot it is when driving on the highway and when in traffic?

4. What is the timing set at at idle with the distributor vacuum hoses disconnected?

5. Exactly what do you mean by "It's down on power"?

6. How long do you let it turn over for each time you crank it?

 

 

 

[1969_Mach1 333]

I guess I missed another one.  Getting good at that.  Gonna stop posting pretty soon.

[Brian Conway 264]

Good questions and suggestions.  For me a quick and eazy check of gas flow at carburetor, coil connections, snapping blue spark, a check on the distributor rotor rotation and a check of the timing mark with a gun would be a starting point.  Brian

[Thin Lizzy 37]

Thanks for your comments and suggestions.

This only happens when the engine is cold.  It starts fine when warm.

The car has an electric choke.

The car used to start fine, until around 2 months ago, around the same time I change the air filter to an aluminum oval.

Yes the engine turns over slower after it is at operating temp, usually 1 minute.

Usually let it turn over for 5-6 seconds.

I've checked the gas flow in the carb and it's working ok.

[Brian Conway 264]

So take the air cleaner housing off and see what happens.  Brian

[Midlife 814]

Midlife/Karnac says your new oval air filter is interfering with your choke mechanism.

[1969_Mach1 333]

I'll risk another post.  First thought was like others, the air cleaner is interfering with the choke mechanism.  But if it's that and all else is okay I'd think it would fire up and die or fire up and stay running as long as he works the throttle.  Or does it fire up and die and the OP hasn't mentioned that?  It eventually does start and run just fine.  No fuel in the carb?  If it's not a simple air cleaner interference issue I'm a little suspicious of the ignition system.  Was the ignition timing reset after the Pertronix was installed?  A cold engine requires more secondary voltage to fire a spark plug.  Marginally weak spark will cause hard starting when cold.  Is the Pertronix properly connected to 12V?  I've never used Pertronix and still not a fan of them.  I've had cars not start cold simply because the spark plug wires were marginal so the spark at the plugs was too weak when cold.

I tend to use this to check for spark at a plug or out of the coil on high output ignition systems.  It should jump that big gap.  There is also one with a center electrode sticking out for stock points ignition.  I'm truly not certain which one is suitable for your ignition system.  But's they are very simple and quick to use when the motor cranks but will not start.  You'll quickly know if you are chasing a spark or fuel issue.

[danno 128]

I'm with 69 Mach. I would never believe it until it happened to me, but it was a coil issue. Check for spark, it is an easy thing to verify.  If it has spark, then carb.  I am not a carb guy, I have a 2100 in my 302.  Very simple.  

[Thin Lizzy 37]

Thanks for the info.  I'll check the coil.

I've found if I press the accelerator down to the floor a few times before starting it, it seems to start better.  Like after the 7th or 8th attempt.

 

 

[Brian Conway 264]

Snapping Blue spark will tell you a lot about the coil and is easy to check.  Brian

[barnett468 418]

On 8/17/2018 at 8:54 AM, Thin Lizzy said:

Thanks for your comments and suggestions.

This only happens when the engine is cold.  It starts fine when warm.

The car has an electric choke.

The car used to start fine, until around 2 months ago, around the same time I change the air filter to an aluminum oval.

Yes the engine turns over slower after it is at operating temp, usually 1 minute.

Usually let it turn over for 5-6 seconds.

I've checked the gas flow in the carb and it's working ok.

COLD STARTING PROBLEM

Ok, the cold start issue has nothing to do with gas percolating in the carb or vapor lock etc, therefore, a carb spacer will not help that, however, this does not mean that there is not some issue with the carb as well that a spacer can't improve or that a better spark won't help,  but the ideal way to approach this is to deal with the biggest issue first which is the cold start issue, and once that is fixed, it may very well automatically improve the hot start issue as well.

As far as removing the entire air cleaner goes to see if it starts easier as Brian suggested, also, try to see if the air filter base is interfering with the choke linkage. You can push the gas pedal to the floor once then carefully remove the air cleaner lid without disturbing the air cleaner base then look at the position of the choke butterfly. Next, remove the base and see if the butterfly closes more. Next open the throttle and see if the butterfly closes more.

If the butterfly closes more at any time with the base off during your inspection, the base is hitting some part of the choke mechanism, and if it is, it may be possible to modify it slightly so it does not. If it is not possible to modify it,  you might get enough clearance by installing a spacer between the air cleaner base and the carb. Most auto shops sell them and there re typically 2 - 3 different heights in the package. I would start with the lowest height if you do that. You will also have to be mindful of clearance between the air cleaner lid and bottom of the hood as it can be very closer on some set ups.

 

HOT STARTING PROBLEM

At least part of this problem could be caused by a few different things and possibly a combination of them. Below are just a few.

Too much initial timing.

Weak starter.

If you have headers the starter may be getting heat soaked, in which case a starter heat blanket will reduce the problem.

Weak battery or a low amp battery.

Weak spark.

Fuel level in carb too high.

Fuel in carb getting overly hot which can cause some of it to be forced out of the carb into the engine. As 69 mach 1 mentioned, a "thermal" (non metallic) spacer will typically reduce this problem, however, lowering the float level can also reduce this problem. If the fuel in the carb is getting hotter than "normal" then my preference is to install a spacer. however, if you are using ethanol fuel, the float level in the carb should be set slightly lower than the factory recommended setting because ethanol "expands" more than straight gasoline when it gets hot.

 

[barnett468 418]

1 hour ago, Thin Lizzy said:

I'll check the coil.

 

CHECKING SPARK/COIL

This test should be done with the engine cold and again with it at operating temp because the voltage/spark can be weaker when the engine and electrical parts are hot.

Other than the methods mentioned, another simple way to determine how weak or strong the spark is, is to park the car in a shaded area, the darker the better, then pull the coil wire out of the distributor then expose the metal end on the wire 1/4" away from  any unpainted portion on the engine (a carburetor base stud/nut or valve cover bolt etc usually works) then either have someone turn the engine over for a few seconds, or jump the front post on the starter solenoid to the small post immediately next to it. A small screwdriver usually works for this but try jumping it before you hold the coil wire so you can get used to it as it can be a little hard to do and the sound of the engine turning over with your head 2 feet away from it can be a little unnerving at first.

You should easily see at least a decent yellow spark. If the spark is faint and yellow, you likely have a weak coil. If the spark is any shade of blue, it is a strong spark even if it is faint. If you have a stock type coil, and it has at least a decent yellow spark, and you do not have a high compression engine, there is no issue with your spark intensity and it is not causing your particular starting problem.