Ive got a sa 200 short hood with a Eismann AM4 magneto. Engine will not quit running when I ground out the cap with a piece of wire to the block. And the terminal on the cap has continuity to the engine block. And where Im really confused is, my meter says I have continuity between the condenser wire(grounded side of the points) and the engine block constantly. And the engine starts and runs smooth ... I turn off fuel then choke it to stop it . Has anyone ever experienced this? Any help would be greatly appreciated! thanks,quinq
Reply:Do you have this manual? https://oldcroak.com/am-series/ On page 7 you see that the points terminal, the condenser terminal and the coil primary winding are all connected together.The other side of the coil primary winding is connected to ground.If the points are closed you will read continuity to ground through the points.If the points are open you will read continuity to ground through the coil.The fact that it starts and runs fine tells me that all of this is wired properly.The wire/contact on the inside of the distributor cap should connect to/touch the terminal on the points with the other wire.I suspect this is where the problem is.Photos of the inside of the magneto/distributor cap would help alot.
Reply:Thanks for the quick reply rexcormack. Yes I do have the manual. But I dont see another wire in there, besides the one coming into the condenser and the yellow one going to the ground side of points.
Reply:Nice photos, thank you!The copper tab that you circled in yellow is what I was thinking of. It should touch the terminal on the endof the yellow wire where it attaches to the points. It looks like it has not touched anything, no mark on it.You might try very carefully bending it up just a little bit or loosen the nut on the points and pulling theyellow wire terminal out a little bit and retighten the nut.Sort of a trial and error thing since it is impossible to see.
Reply:That tab in the cap has continuity to ground when the cap is installed . Yes I bent it out all ready and with ohm meter attached to it.... it makes contact to ground . What I don’t understand is how is it going to stop the spark (or why do I have spark) with it having continuity to the engine block . Thanks
Reply:You are measuring continuity to the block (very low ohms) through the primary winding of the coil if the points are openor zero ohms when the points are closed.The primary winding has very low resistance so it will look like a dead short unlessyou turn your meter down to the lowest ohms range.
Reply:I believe my meter is a auto ranging meter . its a fluke 73III .
Attached Images
Reply:Opps !!!!77III
Reply:Turn the engine by hand until the points open and remeasure it.Since it starts and runs good there is nothing wrong with the magneto.When you put the jumper wire from the screw terminal to the engine block are you holding it there for a while?The screw terminal has to be grounded until the engine completely stops turning, that's why they use a switch.
Reply:Well it’s real difficult to get it to hold the points open as it has a spring loaded snap over feature in the mag to make it easier to hand start.If I do remember correctly I’ve had the meter hooked up and manually opened them with a non conductive ( plastic ) stick...meter still reads the same . And yes I do understand about holding the wire to ground for a while ( but it doesn’t even miss a lick)
发表于 2022-2-9 15:52:27
