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replacement coil mercuy 339-5288

Further to my post of my 9.8 power issues, I was looking for a new coil, part 339-5288.

I found that here in the UK, I could get s CDI Electronics 184-0001 which looks identical.

It has the same primary coil resistance.

BUT it appear the the primary and secondary coils are connected internally and the armature core (which is metal not ferrite) is then connected to the primary negative with a metal strap.

The original coils have a wire that goes to the secondary coil and this just gets squashed up against the engine to make the earth.

So If I put the new coil in, I would have to add a wire from the armature core to earth, but this would also earth the negative side of the primary, will this blow the ignition module?

CDI don't seem to make the coil with a secondary coil earth wire...
 
If you remove that rubber covers, you'll see that the metal core is grounded either way, though by different methods. They are interchangeable far as I can see--I have one of each on a running motor.

Jeff
 
If you remove that rubber covers, you'll see that the metal core is grounded either way, though by different methods. They are interchangeable far as I can see--I have one of each on a running motor.

Jeff

Well sort of, yes.

The orange coils have an isolated secondary coil, so one end goes to the plug, the other comes out on a bit of wire which contacts the core and then earths to the engine.

The primary winding -ve is not connected to earth. It goes back to the switch box.

One the new coil, the primary winding is connected internally to the secondary. The core is connected to the -ve primary terminal with a metal tag.

So electrically they are different.

I don't want to risk blowing a $200 switchbox if its not designed to connect to earthed primary coils...

The service manual schematic shows that the two windings are isolated too.

diagram below.

I have no idea what's in the switch box but the wire going to the -ve terminal is defo not connected to earth inside it.

coils.jpg
 
Me bad. I now recall that the two different types of coils I'm running are both 'blue' coils. (The red, orange, yellow and green coils are definitely different. The blue and black coils are interchangeable.) Of the ones I'm running--both blue--one has the external strap, while the other hasn't--but it also lacks that pigtail in back.

Sorry for the confusion.

Jeff
 
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