When starting a warm/hot engine on mag, do you still need to advance the spark lever and throttle like you do when starting cold?
Mine you do! Bud.
Bill on our 16 it has to be advanced to start on mag hot or cold. I find ours starts best 8 notchs advanced on mag and it does kick back on mag if advanced to far. batt fully retarded
This is what I do. It seems to depend on how you have your initial timing and carburetor set. I start my engine 1926 with the same spark and carb setting whether warm or cold. Extreme cold less than freeze is another story. I have the spark all the way up, if you need to have your spark advanced a little, maybe your initial timing on the timer is not exactly correct. For the carb setting I have to have that down about 3 or 4 clicks. Especially when hand cranking, it gives the engine a little more momentum to keep going once it hits. Your car is a 1914, isn't it? So you are hand cranking all the time? But for me the setting are the same whether starting on battery or magneto. Maybe you should check and adjust if necessary your initial timing and spark handle position. Good luck Mike
Advancing the spark a few notches when hand starting on magneto is for electrical purposes and has nothing to do with whether the engine is hot or cold.
Study the diagram below, if your initial timing is set correctly, you can see if you do not advance the spark a few notches you will be trying to start the engine with a spark that occurs 26.5 degrees ATDC. By advancing the spark lever you can catch the spark that occurs at 4 degrees ATDC which is much easier.
You can find the entire article here. The Model T Ford Ignition System And Spark Timing
Ron the Coilman
Sorry here is the diagram.
Magneto Fig8.pdf (48.5 k)
Is there a simple formula to convert 4° ATDC to notches?
See he following Ford recommended procedure for hand crank magneto starting.
If you read the PDF article cited above you see how this was arrived at.
But remember if the initial timing has not been set at 15.5 degrees ATDC as Ford suggested all bets are off.
Ford also pointed out it is possible to set the spark lever too far advanced.
Ron the Coilman
I guess I always thought that the car wouldn't kick back on mag, but apparently it can?
Bill I'm no expert, but since on mag there is no "constant spark" somewhere to assist in firing as there is on battery, I would think it would be awfully hard to get a kick back on mag. You're generating your spark as you crank. Possibly if you have the lever too far advanced it might but I've never had it past 1/3rd. the way down and never had a problem.
I see some people say 3-4 notches, but some cars have more than 3-4 notches worth of slop in the linkage. Yeah, I know it should not have that much, but the fact is, some do. Mine included. I pull mine down until I feel the slack go out of the linkage, THEN I give it 3-4 notches. Works every time.
Follow Ron Patterson's advice here and on any other Ford ignition issues and you will never go wrong. My first car would start with the battery then switch to magneto and run really well. I followed Ron's advice and should just remove the starter as the battery went bad about 10 years ago and I never replaced it. The car starts fine on magneto and I don't need a starter or battery.
This is a better way to use them as I have had many kick backs with the switch on battery (but never broke my arm) and have never had a kick back on magneto. Not to say it couldn't happen but do exactly what Ron says on every point in all things.
For years I've just fully retarded the spark and give it close to 1/3 throttle. Pull the choke for 1 or 2 pulls when cold and then a pull or two and it's running. If it's cold I stand by the choke wire and give it another tug or two to keep it running. Then walk around and advance the spark 1/2 way and knock the throttle back to a nice idle
If I'm leaving the car after a tour I shut off the gas and put the throttle to high idle and let it run the carb dry and just leave the ready to run. That way the key can't fall out of the ignition by chance
Assuming everything is set and working per Ford recommendations and the spark lever is is advanced more than 10 notches a kick back is possible, but the piston speed is slow and there is little compression with a spark occurring at 18.5 degrees BTDC. I DO NOT SUGGEST ANYONE TRY YOUR LUCK!
Hal is correct, this assumes everything is set and working per Ford recommendations.
Thirteen years ago Steve Coniff and I undertook "The Model T Ford Ignition System and Spark Timing" article to help simplify and understand how the original Ford system worked so the average man could understand how it worked. Frankly speaking, we were both tired of explaining the details time and time again.
At the outset we agreed there would be no complicated formulas or explanations so anyone with a fundamental understanding of an internal combustion engine design could easily understand.
If you use a alternative ignition system, please ignore, but if you have a Model T with the original ignitions system please try to understand these fundamentals.
You will be surprised how it will help when trouble shooting Model T ignition problems.
Ron the Coilman
Not only that, but you will be much happier with your car, once you have an understanding of how it works and therefore how to get it to run properly. You will gain a better appreciation of it. You will not be so tempted to trash the original system and replace it with something else. You might even find yourself leaning toward being a purist. Oops, disregard that last comment. The dozen or two of us on here are already a dozen or two too many in a lot of eyes.
Yeah, at a car show this last weekend I had a guy with a "Huckster" telling me I needed to change to a distributor system for a more reliable car. Karma is wonderful. At the end of the show his "Huckster" wouldn't start so I switched mine to "MAG" and did a slow pull and "Sara Jane" sprang to life... so much for distributors being more reliable
It's simple,step to the front!! If you crank long enough most will learn to position the timer so when the AC power pulse happenes the timer is in the right spot to to pass it on!! Bud.