Mercury 20hp 200 thunderbolt wiring diagram

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mr.stan

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Feb 23, 2012
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Hi - I am after a complete wiring diagram for this motor. It has two coils but not getting any spark to them, so need to retrace complete lot from under flywheel. Hoping someone can help. I don't know the year of manufacture also.
 

MH Hawker

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Re: Mercury 20hp 200 thunderbolt wiring diagram

What you need to do is get a book and test the items before you blindly start replacing a lot of very expensive parts. My motor died awhile ago out on the lake and I had to be towed in, it turned out to be the cdi box but it could of been several things.
 

walkerb

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Re: Mercury 20hp 200 thunderbolt wiring diagram

Had the same problem with my 1972 200 20hp Merc, wouldn't start. Pulled the flywheel so I could get to the ignition and found both the white and brown wires that connect the points to the coils had fallen apart. Have had this problem with other wires on this engine and a friend with a 1976 had similar problems. Was able to get both wires locally a a Mercury dealer and replaced them and it runs like new. The brown wire is P/N 56317 A4 and the white is 56316 A3. The dealer has two more of the white wires but no more brown ones. Hope this helps.
 

flyingscott

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NEED SERIAL# OF THE MOTOR. Why would you open a switch box. Give us a pic the coils are mounted on the back of the motor above the spark plugs. Get a wiring diagram if it's that bad start from the beginning. If it has a switch box pretty basic wiring not much to screw up actually any of those motors 200 20 hp have basic wiring.
 

jbcurt00

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Moved this to a topic about your motor, Krazy
 
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