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SA200 Magneto No Spark

48K views 62 replies 11 participants last post by  Jim55  
#1 · (Edited)
Hi all,
I just scored an SA200 in pretty good condition. It came with a trailer, toolbox and was pretty inexpensive too!

The problem is no spark out of the magneto.
It has new points, new rotor and a new condensor courtesy of the previous owner in his attempts to get some spark. There are also new spark plug wires.

The points are gapped at about .030 or so. I eyeballed it since I don't have a set of feeler gauges handy.

There are no markings on the magneto. Nada. Nothing. No manufacture name or model number.

I used a meter to see if the coil in the magneto had continuity between the two wires (coming from the coil) and it did. I'm not got at electrical stuff so that's the only test I did with the meter. There was continuity.

I spun the drive gear tabs around while I held a finger near the breaker points and got a little shock. I also spun it around while holding my finger on the metal tab coming off the coil in the magneto. I got a little shock from that too.
I put it in the engine and cranked the motor around for a few revolutions and didn't get anything from the spark plugs. (I have the spark plugs laying up on the engine head and plugged into the wires.)

I tried cranking the engine around with the wire that goes to the side of the magneto both connected and disconnected. Same result, no spark.

There are 2 gears in the magneto. One is made of fiber and marked with an A and a C. One tooth on the little steel gear that meshes with the fiber gear is supposed to be marked and mesh inbetween the A and C. I can't find any marks on the little gear. I don't know if the previous owner had the magneto totally apart and didn't line up the gears properly, and without the mark on the smaller gear I can't tell. I know they are supposed to be timed correctly in order for the points to open while the rotor is in the correct position.

Any ideas about what to check?

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#2 ·
Shanghyd you need to be able to identify the magneto to work on or order parts. I know you want an immediate answer, and maybe someone can help you soon, but, besides many parts for the SA 200, there are procedures explained on the CD I'm referring here that will help you solve the problems and identify your mag. Go to www.weldmart.com and at the top of their page is a place to order their CD/Catalog. The CD has a breakdown of the various magnetos used on the SA200s. It actually explains procedure to use to fix and test them, too, something I haven't been able to find anywhere else. They won't let you copy it to put it online tho. You have to get the CD from them, takes about four days (for me) and it's FREE! Good luck!
 
#3 ·
#4 ·
Adding the photos makes a difference! You have got a Fairbanks-Morse FMX4B16A-1 magneto. Like Duaneb55 said, set the points at .015. That should make a difference. Without a feeler guage handy, the cover on a paper matchbook will work.
 
#5 ·
Thanks for identifying the magneto for me. I'll order the cd from the link you posted.
I closed the points a bit more. They are closer to .015 now.

I've posted another picture of the two gears that mesh together in case anyone is able to spot the mark on the little steel gear that I am supposed to line up with the fiber gear.
I'm pretty sure that the gears are off because I had to assemble the magneto when I picked up the welder.

If anyone knows of a way to line them up or to verify that they are lined up correctly it would sure help out.

 
#6 ·
I haven't found any info on this yet but if I had to guess I'd say the tooth that lines up with the shaft flat. First thought is that the 'C' stands for 'Continental' or ?? and the 'A' may be 'Advanced' or ??. Not sure the small gear lines up in between the two but I'm only guessing here.

That missing fiber gear tooth can't be too good either.
 
#16 ·
If you turn the mag in reverse rotation to the point where the points are just opening, does the rotor line up with any of the plug wires?

A test light and a 12v supply or a VOM might be helpful.
Although I have put together a few basket cases and had to resort to the method I mentioned above.
That would work for me in absence of any other information.
 
#8 ·
OK, the 'C' is the timing mark for 'Clockwise' and the 'A' for 'Anti-Clockwise' rotations. If the small gear tooth isn't the one lined up with the shaft flat, the gear may have been installed with the mark on the opposite side.

Still looking.
 
#9 ·
OK, the CD won't let me copy the photos or the text, but, on a clockwise magneto the rotor gear (metal) (small) must mesh so the red tooth goes between the two teeth on the distributor gear (fiber) (large) marked "C" The metal and fiber is how my mag is. Don't know if they're all the same?
On the counterclockwise magneto it meshes between the two teeth marked "A" The drawing of the rotor gear is in B&W so no color but it's also marked with several center point marks in the drawing. I removed the "c" clip from my rotor gear and found no marks or letters on either gear. No paint either, hope you have better luck.
 

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#11 · (Edited)
My mag will spin by hand only counter clockwise from the bottom. Try to spin it clockwise and it locks. therefore I'm assuming from the bottom? Which would make it the rotor gear, altho the actual rotor goes on the shaft identified in the manual as the distributor gear. How confusing is that?
 
#13 ·
I took my mag apart to clean it as it was full of oil. I removed only the rotor gear (small) but had no idea it would need timing with the larger gear. I got the CD with the manual on it and now I am not sure how to time the two gears together w/o any marks. I'm still a long ways from putting the SA 200 back together (fixed income), so I'm not in a hurry, but it WOULD be nice to know.
 
#14 ·
That place where it feels like it locks up is the impulse spring starting to wind up. That is the direction of rotation. if you force it through that point you will here a snaping sound and get a hot spark from the coil.

I always mark them with something when I take them apart.

Although I have put together a few basket cases and had to resort to the method I mentioned above.
 
#18 ·
I was going to say that but I was busy looking for this. Right out of the Fairbanks-Morse information and still as clear as mud if you can't see any marks. I go with Joe's method.
 

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#19 ·
I'd like to say thanks to everyone that has put effort into this issue.
I tried a couple of different gear positions and managed to get some spark going.
I ended up setting the point position to where it was either just before it opened or closed, I'm not sure which position it was. Then I set it where the rotor was pointing to one of the wires.
I cranked the engine over by hand until #1 was on the compression stroke then I lined up the rotor with #1 and bolted the magneto in. The engine fired up for a second then died. I cranked it around but the battery died. So I'm getting there. At least there is spark now.

Thanks for all the effort everyone.
 
#20 ·
Well it sounds like progress is being made. Although one can time the mag to #1 cylinder (any cylinder as far as that goes) the proper procedure calls for timing a mag to #4. You can find it step by step here http://billswelderrepair.com/magneto-timing.html and Bill or Kaye can help out too if needed. Just give them a call.
 
#21 ·
Progress has ground to a halt.
I have spark coming from the magneto. The magneto is timed to #4 cylinder but I have yet to find out if the gears are correct in the magneto because the engine won't crank over long enough.
I hooked up a fresh battery. I took the one out of my car so I know its good.
I hit the start button and it will crank around at a pretty good clip for about 6 revolutions then quickly come to a stop. I think I get about 8 revolutions before it stops. I know it doesn't run the battery down that fast because I'll put the battery back in the car and it will start right up.
I'm thinking something is getting hot and not working as it should. The ground and positive cables get warm/hot. They both have good connections to the battery, the ground lug on the frame and the starter solenoid lug. The starter solenoid gets hot too.
 
#22 ·
Bad starter.
 
#23 ·
Still no joy. I replaced the starter and have spark coming from the magneto but the engine won't start. It cranks over fine and has good compression.
I took all the spark plugs out and layed them on the cylinder head. I crank the engine around and each of the spark plugs have spark. It is getting fuel. I even used a can of starting fluid.
I'm thinking that its sparking at the wrong time due to the internal timing of the magneto.
I timed the magneto to the engine using the instructions at billswelderrepair.com.
http://billswelderrepair.com/magneto-timing.html
I was able to line up the gears where the marks meshed together as indicated in paragraph 3 of the instructions.
I wasn't able to find a T on the flywheel but I found a red mark. I also found something that looked like O|O. The red mark was lined up when the marks on the teeth were meshed together.
Any ideas?
 
#25 ·
The rotor is pointing down and to the right as I look at it from the generator side. 4 oclock. The small tab that makes contact, or rather, comes very close to the spark plug wire terminal is in the 4 oclock (or thereabouts) position.
 
#26 · (Edited)
But what cylinder is at/near TDC at that point and which plug wire is connected to the 4 o'clock mag tower?

edit: Basically, Joe may have it.
 
#31 · (Edited)
I cranked the engine over by hand until #1 was on the compression stroke then I lined up the rotor with #1 and bolted the magneto in.

. . .The engine fired up for a second then died. . . .

. . .I cranked it around but the battery died.

. . . Number 4 is on its compression stroke when the rotor is pointing at the 4 oclock position
Based on the above, I'm with Oldiron2 and betting on stuck valves.

Shanghyd - Does each cylinder still have good compression?
At least good enough to blow your thumb away when each cylinder hits compression?

Good Luck
 
#28 ·
It might be worth using a timing light to be sure your spark is occurring when you think the Mag is firing. If there is no flywheel or pulley to watch the mark on, perhaps a mark on the gears would suffice.

If you are fairly sure that you are getting a good spark at the correct time and it still won't fire, you might consider whether the valves are opening; I don't know what type of engine you are working on, but if it's a Flathead, it could have the timing gears missing teeth or a chain broken, so the cam isn't rotating. Do you get any suction at the carb, or pressure from the exhaust, when it cranks over?
 
#29 · (Edited)
and that is the wire that is going to number four? Did you verify that number four was on the compression stroke? I usually pull the plug and rotate the engine with my thumb covering the hole. When it tries to blow my thumb off the hole I know it is on the compression stroke.

Did anyone tell you about plug wires? You know it should have solid plug wires on it such as "Packard 440". I don't think that is your problem. But while you are working on spark, it might be a good idea to make sure you have the right wires on it.

Go to some parts place like a NAPA or other Old School parts store for the wires. Autozone/Pep Boys will think you want wires for a Packard.

You could try this link http://www.thehotrodcompany.com/shopnow/show_item.asp?product_id=spw_PAC4401


The plugs should be Autolite #3116. Not # 386 or # 388 as they are resistor plugs. Champions are crap. I know someone will tell you different, but they are always the first to fail when I test them under compression.