78 40HP Mercury 2stoke No Power from key to cyclenoid (thunderbolt ignition)

pos boat

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May 23, 2012
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2
Ok guys/gals I need some help. Went out to start boat when i turned the key i had a loud click coming from the cyclenoid and the electonic choke was working but the starter would not turn. So I tried to jump the cyclenoid to test the starter and the starter still would not in-gage. After doing this I lost power to the cyclenoid no click and no choke. I replaced the starter because it was seized up and replaced the cyclenoid but I still have nothing when I turned the key (brand new battery also) Can anyone please tell me if there is a fuse on a 40HP Mercury, Ive been told there is but I cannot find and cannot find out why I have no power. Any info would be greatly appreciated. Thanks
 

keithmylum

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Joined
May 7, 2012
Messages
19
Re: 78 40HP Mercury 2stoke No Power from key to cyclenoid (thunderbolt ignition)

Ok guys/gals I need some help. Went out to start boat when i turned the key i had a loud click coming from the cyclenoid and the electonic choke was working but the starter would not turn. So I tried to jump the cyclenoid to test the starter and the starter still would not in-gage. After doing this I lost power to the cyclenoid no click and no choke. I replaced the starter because it was seized up and replaced the cyclenoid but I still have nothing when I turned the key (brand new battery also) Can anyone please tell me if there is a fuse on a 40HP Mercury, Ive been told there is but I cannot find and cannot find out why I have no power. Any info would be greatly appreciated. Thanks
No problem, two things first do you own a volt meter? Second do you have the wiring diagram?If so first check to see if you have 12v at the battery. Set your meter to dc. Most of your componets are going to have a red cable coming off of them. Just put one side of the volt meter on the post with the red cable coming off of it and the other to any unpainted part of the engine. Follow the wiring diagram just like a map start with the battery and then move to the next component inline on the diagram whereever the power stops is going to be your problem. I have a 71 40hp and it does not have a fuse, not sure about your 78 model.
 

pos boat

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May 23, 2012
Messages
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Re: 78 40HP Mercury 2stoke No Power from key to cyclenoid (thunderbolt ignition)

Thanks for the help :) Going to get a volt meter tomorrow. I dont have a wiring diagram..would u know where I can get 1? Thanks again for the help
 
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