URGENT - electrical help.

[dunginhawk]

Good evening. I have a full day of fishing planned for tomorrow (my wives fathers day gift) come out today to test the boat and the 20amp fuse on the motor kills every time I turn to start it.
Back story. 40hp merc 4 stroke 2005 model. Pristine condition

1. Undid battery to jump start my car earlier in the week.
2. Put everything back where I thought it went. May have missed a wire, and tripped the fuse then (could have been a problem before, but don't know).
3. Isolate down to just 2 motor wires to battery, try again, BLOWN fuse.
4. Its blowing the 20 amp fuse when I turn the key to start, but wont blow it when I turn it to on. So trim etch works. But wont start without blowing.
5. I have isolated it to where all the red wires go in to the starter. There are 4 things that screw in there. The large wire that runs to battery (not the issue), a single red wire that runs to an inline fuse (not tripped) (also not the problem). A set of 2 thick wires that I think run to the rear of the motor (not the issue), and then this set of 3 pretty stared all red wires that I am having a hard time tracing. 1 appears to be for the alarm (because it wont work without that wired in). The other 2 I have NO idea.

Any ideas guys?> please help, I'm desperate...
Thanks in advance.

 

[Yamadogg]

Are your fuses actually blowing out, or do you lose all power when you turn the key to start ( then it starts out Ok again after changing the fuse) ? Make sure your fuse holder has clean bright metal . Here's a post on another forum ( not boating _ not exactly your problem ) pay attention to the parts about clean contacts - I had a situation somewhat similar to yours. Turned out my fuse holder had enough corrosion to be problematic until I thought to clean it up - now it's an annual maintenance item for me.