'72 Mercury Thunderbolt Ignition wiring?

joshua27

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Apr 12, 2013
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I'm trying to get an old Mercury motor running that I acquired recently. The motor according to the serial number is a '72 model Mercury 500 50 HP with Thunderbolt ignition. The problem I'm having is that the coil above my distributor cap which says "lightning energizer" has 3 wires coming out of it and they are rotted off flush. how do I replace these wires and what is the easiest way to do so?

On a side note this is the first time I've ever worked on a boat motor so I'm a complete newbie at this.

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Laddies

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Re: '72 Mercury Thunderbolt Ignition wiring?

First use the utter most care working on that engine most driver parts are NLA like the wire you need but that wire can be replaced, it requires removal and tear down of the driver assm. Here's a parts beakdown for the driver, :: iShopMarine.com ::
and here's then only place with parts and prices for that engine, prices for cap and rotor if you break them disassembling the driver come to more than $600 so be careful. 3,4 & 6 Cylinder Models
 

joshua27

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Apr 12, 2013
Messages
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Re: '72 Mercury Thunderbolt Ignition wiring?

Thanks so much for the quick reply! How do I actually go about removing the ignition driver from the motor?



First use the utter most care working on that engine most driver parts are NLA like the wire you need but that wire can be replaced, it requires removal and tear down of the driver assm. Here's a parts beakdown for the driver, :: iShopMarine.com ::
and here's then only place with parts and prices for that engine, prices for cap and rotor if you break them disassembling the driver come to more than $600 so be careful. 3,4 & 6 Cylinder Models
 

Laddies

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12,218
Re: '72 Mercury Thunderbolt Ignition wiring?

To remove the driver you must take it off in one piece, disconnect the plug wires from the plug not the cap as they are screwed into the cap, remove them from the clamps that hold them to the side of the engine, disconnect the 3 rotten wires from the driver at the switch box, remove the plate that holds the idle and spark advance screws from the engine do not turn any of the adjustments on the stop screws, disconnect the control cable from the spark advance arm, then the 4 bolts that hold the driver to the tower and it should come off. Piece of Cake!
 
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