Spark Retard or ?

bputhuff

bputhuff

Junior Member
I have a '29 Roadster that is an aging restoration, but looks original (stock). I'm new to the Model A and its quirks, so please be patient with my dumb questions..

Per instructions, I push the left hand lever all the way up (fully retarded), pull the choke and press the starter. When it fires, I release the choke and pull the left hand lever down.

It runs crappy.

If I raise the lever, it smoothes out. Keeping it down (advanced) sounds like it's running way too rich, with surging and stumbling. Fiddling with the mixture control on the choke doesn't help, only retarding the spark seems to be helpful. Also, with the spark retarded, it backfires on deceleration, which doesn't seem to happen when it's running poorly (advanced).

Advice? Suggestions?

Thanks

Bob
 

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Hi Bob, pretty car. Did you just pick it up. Seems like I saw it on Craigslist or Ebay...

Anyhow, when the car starts are you pulling the spark advance all the way down? Mine will run crappy that way too. Every model A seems to have it's own character, but most run best about 1/2 way down. It is your job to move it to the position in which it runs best. If that is all the way up, then somthing isn't set up properly, and I must honestly confess, I haven't messed with my distributor yet (new to A's somewhat also) so I can't tell you WHAT would cause your lever adjustment to behave differently. At about 1/2 way down, mine purrs like a kitten.

Tom
 
I'm a novice too, but am learning a thing or two as I go. I would suggest you set the points and time the engine before you do anything else. If your running real rich, you will never get the adjustments to respond properly. Get a good carb that has been flow tested to get rid of your rich condition. That along with the timing set correctly should get you on the way to smoothing her out. JMHO
 
It sounds like the timing is too advanced. When the spark lever is brought fully up, the timing is retarded back to where it normally would be if the timing were set properly and the lever were in the down position.

I believe that the posting right before mine gave you Marco's website. He has a very good tutorial on setting the timing and adjusting the points (which could also be part of the problem) and I refer to it every time I work on mine.

My A was running rough the other day. I reset the points only about .003" less, and now it runs great. Small changes can make a real difference.

Nice looking roadster, by the way.
 
bputhuff said:
I have a '29 Roadster that is an aging restoration, but looks original (stock). I'm new to the Model A and its quirks, so please be patient with my dumb questions..

Per instructions, I push the left hand lever all the way up (fully retarded), pull the choke and press the starter. When it fires, I release the choke and pull the left hand lever down.

It runs crappy.

If I raise the lever, it smoothes out. Keeping it down (advanced) sounds like it's running way too rich, with surging and stumbling. Fiddling with the mixture control on the choke doesn't help, only retarding the spark seems to be helpful. Also, with the spark retarded, it backfires on deceleration, which doesn't seem to happen when it's running poorly (advanced).

Advice? Suggestions?

Thanks

Bob
Click to expand...

Sounds like it is working fine if you mean that you bring the lever all the way down.

Start the car, get up to speed, lower the lever and the engine will increase in speed. Stop lowering the lever when the engine stops increases speed. The faster you go the lower the lever.
 
if you happen to read the original Ford Instruction Book or a reproduction copy, it explains that you start the engine with the lever up. Once started, it idles and runs around town or drives in "normal" conditions at half mast. Only at high speeds is the lever advanced to the bottom. That's with a stock head and under no excessive load such as hill climbing. If you have a H.C head, advancing the spark to about 28 degrees, or 4 clicks up from the bottom is the max recommended by many of today's engine builders and Les Andrews. If the car needs more advance, you will feel a power increase when you advance the lever. If you advance and it does not increase power, pings or decreases power, you have gone too far. At Idle, if you pull the lever all the way down and it runs crappy, its because its way too far advanced. Driving it with too much advance will ruin your bearings pronto.

Anyone with their first Model A should read a copy of the instruction manual. Its full of useful information about how to drive and care for a Model A. Its well worth the relatively cheap price.
 
Thanks for the help.
This is a real adventure.
Who knew I would need to be so intimately involved with the ever-changing needs of an engine. The advances in technology over the past 81 years are impressive.
Thanks again,
Bob
 
That's one of the things that makes a Model A a Model A - you have to DRIVE it. My Model A's seem to run best with the spark lever at the 9 o'clock position - that would be about halfway down. If it is timed correctly, you should be able to hear each cylinder "fire" with the throttle up. As you advance the spark, the engine will smooth out and run seemingly faster. The Model A is a forgiving car; don't be afraid to experiment somewhat. As the other replies have correctly stated, no rule is set in stone for all cars. FYI, my son and I drove my '30 Tudor to the Columbus Ohio Goodguys twice this weekend. That would add up to around 250 miles. The car ran fine, but was a little intimidated by all the non-stock Model A's in attendance.
 
HOW TO DRIVE A MODEL 'A'.

HowtodrivetheA-1.jpg

Chokeing: Foot pressed on the starter button. Starter turns over the engine. Pull choke lever up and back down ASAP AS THE ENGINE IS TURNED BY THE STARTER.

Holding the choke open for more than a few revolutions can flood the induction system...you'll play heck cleaning [leaning] that extra fuel out.

skip.
 
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