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-   -   "Sticky" ignition (https://www.fordbarn.com/forum/showthread.php?t=135693)

shaefer 04-01-2014 10:00 AM

"Sticky" ignition
 

I'll see if I can describe "sticky ignition" the best I can. First off, car is a '31 Cabriolet all original engine, etc., etc., etc. Just so we're clear on what hardware we're working with here.

When I depress the starter button on the floor the engine turns over fine enough. It may be slightly weak, but it gets through the revolutions well enough. At least it does right up until it's about to ignite. If a regular revolution under starter motor power (before startup) sounds like "rauhrauhrauhrauh", then the moment before the engine starts sounds like rauhrauhrauhree - with an abrupt halt right at the very end there as if the cylinder pressure were too much to overcome. After that abrupt halt, it does not start up right away. Occasionally, if I stay on the starter, the cylinder will get a spark just after the halt and then it will come to life.

The engine runs fine, has plenty of oil and is well timed. The battery is probably near the end of its life, although like I said, it does have enough juice to turn the engine over.

And this is what has me confused. I would chalk it up to a weak battery and therefore a weak start, but it does turn over. Is there something I'm missing about the mechanical process that would answer this, or is this typical of a battery that needs replacing?

Thanks for the help! This is my first post. I've been maintaining this car with my dad since 1997, when I was only 15. Between the two of us, the car spent no less than 7 straight years as a daily driver! By far the best car I have ever owned. As the weather is just getting to be perfect, I am hoping to have her up and running just like the reliable old Belle that she is! Thanks for the help!

- Mark

Doug in NJ 04-01-2014 10:13 AM

Re: "Sticky" ignition
 

Is the timing too far advanced? Is the spark lever all the way up when starting?

Doug

shaefer 04-01-2014 10:21 AM

Re: "Sticky" ignition
 

The spark lever is fully advanced (all the way down) during startup. The start up routine is: advance spark level to the fully-down position, one hand on the throttle and one on the choke, depress the ignition. If it doesn't kick in right away then give one short pull on the choke and feather the throttle just a bit. That works every time...up until recently.

Spark advance lever all the way down (advanced) is where it runs best and, honestly, we've only ever used the spark advance either all the way up for idling or all the way down for driving.

johnbuckley 04-01-2014 10:28 AM

Re: "Sticky" ignition
 

Gosh, fully retard is best for easiest starting, honest!
and try cleaning the points ( as ever!)

Mitch//pa 04-01-2014 10:30 AM

Re: "Sticky" ignition
 

it must be all the way up (fully retarded) when starting hot or cold..

when timing the engine it must be up for that also.....

shaefer 04-01-2014 10:32 AM

Re: "Sticky" ignition
 

Definitely "up" for timing. I am now trying to remember if that's right about how I start it. It's one of those things that I've done so many times, it's second nature. But I think we keep it advanced during start up and then retard it back once its running for idle. Let me check on that and get back.

newshirt 04-01-2014 10:53 AM

Re: "Sticky" ignition
 

The spark lever must be all the way up when starting, as mentioned by Mitch.

When I first read your description, it sounded like the spark was advanced. (As if you had pulled down on the spark lever or the engine wasn't timed right.)

When the spark is advanced (spark lever pulled down), and a cylinder fires, the engine compression works against the starter motor. The starter may halt or even kick back. Here's why: The piston is being pushed down by the engine compression while the starter is trying to push it up.

But hey... you may also have a weak battery.

Purdy Swoft 04-01-2014 11:03 AM

Re: "Sticky" ignition
 

Maybe even a bent armature shaft if it has been cranked with full advance. I've had it happen. As long as the starter drive isn't locking up you are probably OK.

Tom Wesenberg 04-01-2014 11:16 AM

Re: "Sticky" ignition
 

If you tried starting with the spark lever advanced, then you're lucky you didn't try the hand crank.:eek:

Greg out west 04-01-2014 12:52 PM

Re: "Sticky" ignition
 



Hi Shaefer,,


First thing I'ed check is what kind of Spark you are getting as you start it..Pull the center lead out of the dist & hold it close to the Head..You should get a nice blue spark...as it turn's over...


If the battery is old /weak the starter will take all the "juise" & not much left for the ignition...My car after "restoration" would start fine, till the coil got hot, then wouldn't restart ...A new coil fixed that..


If your getting a good spark,,then the starter could need "work". I had a Cable go bad on the Terminal end..Car wouldn't crank,,,But would start with the crank...took awhile to figure that one out,,,,



Greg Out West

Patrick L. 04-01-2014 12:59 PM

Re: "Sticky" ignition
 

Like the others have said.
Spark lever [ left lever] fully up for starting ! Then down way half way once running.

From your post, it sounds like thats your problem.

Tom Endy 04-01-2014 01:51 PM

Re: "Sticky" ignition
 

My suggestion: If you have not done so in the past 20 years remove the floor boards and the battery and disconnect the ground cable from the frame. Take a disk sander and clean the rust and corrosion off the boss on the frame where the cable attaches. Wire wheel or bead blast the cable, nut, and bolt and reassemble. This is the most neglected electrical connection on a Model A, it is out of sight, out of mind, and not easy to get to.

Tom Endy

shaefer 04-01-2014 05:44 PM

Re: "Sticky" ignition
 

Thanks for the great suggestions. I can confirm that I have been advancing the spark all the way before starting. Also, I can say that I am not entirely sure why I was doing this or how the habit started because I consulted my cheat (that I made when I was only 16 in 1998!) and that was on the instruction. Weird how habits creep up.

The battery is indeed too far gone to be able to get a really good read on the health of the coil, so a new battery will be going in tomorrow. One thing I will definitely do that I have most certainly neglected to do in at least the last ten years is to clean all the battery and ground contacts. If the coil is in good shape, then hooray! I think it probably is since it runs perfectly well. Retiming, etc will follow and it's off to the races! (I hope!)

Thanks for the good advice.

newshirt 04-01-2014 07:12 PM

Re: "Sticky" ignition
 

That's good news, Shaefer. It's always nice to get positive confirmation on issues like this. See you around!


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