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Magneto issues on a D7

Magneto issues on a D7

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funflyer26
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I am trying to start up my 1953 D7 (D7-7M1629SP) after about 3 months sitting outside (it was covered with a tarp). There is 2 of the three required items for ignition of the pony motor, I have fuel and air but no spark. I can pull the spark wire from the plug and get a spark from the end of the wire to the engine block but as soon as the plug is connected then I don't get a spark to jump the spark plug gap. I bought brand new spark plugs (D16 I think they were) but didn't make any difference. I know that there is voltage due to the sparking of the wire directly against ground and from it knocking me back from the tractor when holding it wrong.

The next thing I was thinking about trying is to take apart the magneto and clean the points but I'm not sure that's valid since there is some amount of voltage coming through. If the magneto does need cleaned, how do you take it off? I have the books for it, but haven't found anything other than the parts book which doesn't help very much to take it apart. Can I clean the points without taking the whole thing off the tractor?

Thanks for any help.
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Fri, Apr 13, 2012 11:39 AM
gemdozer
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You do't need to pull out the magneto for clean the point and used a fine sand paper
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Fri, Apr 13, 2012 5:23 PM
Old 3T lover
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Reply to gemdozer:
You do't need to pull out the magneto for clean the point and used a fine sand paper
If you have a good blue spark from the spark plug wire to the block, can hear a good "crack" sound when it jumps from wire to block and it feels like you have a broke arm when it bites you, you have a bad spark plug or you're just not making a good ground when checking with wire on the plug.

If you have a red spark from wire to block, you need to do a little magneto cleaning/work.
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Fri, Apr 13, 2012 6:01 PM
funflyer26
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Reply to Old 3T lover:
If you have a good blue spark from the spark plug wire to the block, can hear a good "crack" sound when it jumps from wire to block and it feels like you have a broke arm when it bites you, you have a bad spark plug or you're just not making a good ground when checking with wire on the plug.

If you have a red spark from wire to block, you need to do a little magneto cleaning/work.
So I should be able to pull the 4 screws on the front of it to get to the points right? I only get a super tiny but still blue spark when holding the wire directly up to the block and it only made my hand tingly for a minute when I got zapped, getting zapped by a lawn mower spark plug I remember being worse.
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Fri, Apr 13, 2012 7:23 PM
Old 3T lover
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Reply to funflyer26:
So I should be able to pull the 4 screws on the front of it to get to the points right? I only get a super tiny but still blue spark when holding the wire directly up to the block and it only made my hand tingly for a minute when I got zapped, getting zapped by a lawn mower spark plug I remember being worse.
Ok... you need to take some fine sandpaper and clean the points, the rotor button, the brass contacts in cap and the spring loaded carbon thingies in the cap.

A good strong mag will have a 1/4" to 1/2" blue spark.
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Fri, Apr 13, 2012 7:46 PM
daron
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Reply to Old 3T lover:
Ok... you need to take some fine sandpaper and clean the points, the rotor button, the brass contacts in cap and the spring loaded carbon thingies in the cap.

A good strong mag will have a 1/4" to 1/2" blue spark.
Possibly could be bad capacitor/condenser.

Daron
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Fri, Apr 13, 2012 10:23 PM
8C 361
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Reply to Old 3T lover:
Ok... you need to take some fine sandpaper and clean the points, the rotor button, the brass contacts in cap and the spring loaded carbon thingies in the cap.

A good strong mag will have a 1/4" to 1/2" blue spark.
I recently went through this with my 1H D8. I found it easier to take the cap off without removing the mag. I took the points out and cleaned them. Those old mags usually have better points in them than can be bought today. I have been known to go after them with a dremmel tool to get down past the pits to a nice clean surface. Replaced points and gapped them with a match book. She starts good now.

Tom
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Fri, Apr 13, 2012 10:31 PM
u-joint
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Reply to 8C 361:
I recently went through this with my 1H D8. I found it easier to take the cap off without removing the mag. I took the points out and cleaned them. Those old mags usually have better points in them than can be bought today. I have been known to go after them with a dremmel tool to get down past the pits to a nice clean surface. Replaced points and gapped them with a match book. She starts good now.

Tom
good advise here! all the cat starting engines i have fiddled with just need the points cleaned. i just drag some fine sand paper through the points. after you have done this be sure to drag a dollar bill or some paper through afterwards. the filings can bridge accross the points groinding them out if you do not clean them afterwards. check the gap also. this will all be fun if you still have the belly pans under it.
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Sat, Apr 14, 2012 1:10 AM
funflyer26
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Reply to u-joint:
good advise here! all the cat starting engines i have fiddled with just need the points cleaned. i just drag some fine sand paper through the points. after you have done this be sure to drag a dollar bill or some paper through afterwards. the filings can bridge accross the points groinding them out if you do not clean them afterwards. check the gap also. this will all be fun if you still have the belly pans under it.
yeah, that comment about the fun to be had with the belly pans on is what I was afraid of. Yes, I only have sketchy access to the cover from the top/side. It should be an interesting afternoon of trying to get that cover off.

Thanks for the input!
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Sat, Apr 14, 2012 2:16 AM
8C 361
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Reply to funflyer26:
yeah, that comment about the fun to be had with the belly pans on is what I was afraid of. Yes, I only have sketchy access to the cover from the top/side. It should be an interesting afternoon of trying to get that cover off.

Thanks for the input!


Yeah I approached mine from the bottom and it was not real easy at that. I took out the points and it would help to have a right angle screwdriver.

I have found that if you take the points out and inspect them they often have a deep pit in them, they can be made to work by sanding them but if you can get down past the pit they work real good. It is not going to be easy to get in there to clean them.

Maybe it would be easier to pull the mag out.
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Sat, Apr 14, 2012 4:00 AM
Old 3T lover
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Reply to 8C 361:


Yeah I approached mine from the bottom and it was not real easy at that. I took out the points and it would help to have a right angle screwdriver.

I have found that if you take the points out and inspect them they often have a deep pit in them, they can be made to work by sanding them but if you can get down past the pit they work real good. It is not going to be easy to get in there to clean them.

Maybe it would be easier to pull the mag out.
It's real simple to remove the mag and work on it and then put it back on.
...as long as you don't mess with the internal gears of the mag getting it back in time should not be a problem.

After you've cleaned and tested it, trip the impulse a few times until you figure out which wire is for #1 and which is for #2. Go ahead and trip mag for #1 and then with very light finger presser, get the slack out of the impluse mechanism. Then with both plugs out of pony motor turn pony engine with fingers over both spark plug holes. You will discover that the engine fires 1-2 and then exhausts 1-2 and then back to firing on 1 & 2.

Now turn pony engine until #1 has compressed all the air out of that cylinder and maybe just slightly past top dead center. The do-dad on the mag and the slot in the front of the pony should just about line up and be in time now. #1 has fired in the mag and #1 piston has compressed and in position of having just fired. Put the mag on, lay spark plugs on top of engine with #1 at #1 hole and #2 at #2 hole and turn pony with your fingers over the holes. When #1 stops compressing #1 spark plug should fire and doing the same for #2. It's in time, install plugs and crank it up.
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Sat, Apr 14, 2012 4:40 AM
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