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mercury 115 optimax 20 amp fuse blowing ?

Mr.ed

Mr.ed

New member
hi , I have a 2004 Avalon with a mercury 115 optimax aslo 2004 , 2 stroke / 3 cylinder. Here's whats going on. 08/11/13 I go to the boat after using it all day 2 days before. I turn key and I get nothing. Next day I come back with fuses and change the blown 20 amp. Boat starts without a problem so I take it out fishing and stop several time at some of my secret fishing holes. I decide to head back to the dock for the day. hahaha I blow the fuse again luckily for me I bought a couple of them. I change it again and blow it again. time for towing ( thanks uncle mike) so this is whats now I turn the key to the on position and I here the beep witch is normal and all my gauges are working in the on position also tilt will work in the on position As soon as I turn key to start I am blowing the 20 amp accessories fuse immediately. things I have done the battery is good and the starter with the solenoid are all good. I had them tested all is good there :) I don't know how to check the starter ignition with out taking it out and putting new one in, but then again I don't believe that would be part of the 20 amp accessories department. Tomorrow I am going to check wiring underneath boat. I'm thinking of wiring or who knows. Any suggestion on a step by step to make this easy lots of wiring on here. Please help before the 3 pontoons get a sledge hammer to it or a ride down the river and not going through the locks instead right over the dam Dam. lol
 
If the fuse is attached to a red wire follow it and look for a scuffed bare wire touching ground. Take your time. You can disconnect the main engine plug and inspect for corrosion.
 
Hey guyjg Thanks for the advice. It is red I will definitely check first thing tomorrow and follow that wire. i never checked the main engine plug. i'm on the job learning. haha. thanks for the tips again. I will let you know when this turns over with no blown fuse. Thanks Mr Ed
 
Per my service manual:

Outlet of fuse is red/purple stripe to pin 8 of the engine electrical harness. Mating connector from the Quicksilver Commander 2000...the one with the exposed box and cables and fast idle is on top rear of the control box, uses a red wire continuing from pin 8.

Next off to the ignition switch to power the starter solenoid (yellow/red stripe) in the START position, and power to the engine electronics via the purple wire on pin 2 of the connectors mentioned earlier.

A second wire leaves that same terminal on the rear of the ign switch and goes through a bayonet single wire connection where it becomes a brown/white striped wire that goes up to the trim switch in the handle of the remote. From there power goes to your up or down trim relays as you select which function you want. At the trim relays, it energizes either relay and that's the end of the line there.

The purple wire on pin 2 goes back into the engine to power the oil warning module and the over rev limiter if so equipped. Then last is a test plug that is used for whatever test function you may want and has a rubber plug in it.

The two modules are easy to troubleshoot....just unplug them long enough to decide if they are the smoking gun or not.

The red wire to the remote PTT switch unplugs from the brown/white striped wire so you can trouble shoot all that easily.

That really leaves the wire to the ign switch and the wire to the trim switch on the side of the engine.

So, you have plenty of places to look. Name of the game is divide and conquer. Looks like with the 2 modules and the red to brown/wh. disconnects, it gets real simple real fast.

Good luck.

HTH,
Mark
 
Thanks Mark i'm headed there now. Great instruction I will follow and conquer. We will win eventually. I'll let you know when I get this started. Thanks again Mark Mr.Ed
 
Hey Guyjg and texasmark thanks for helping out. Sorry I didn't reply earlier but I was celebrating our victory. We won and it feels so good. The problem was the micro switch aka neutral safety switch in the throttle. It was shorting out at the connection. It was the yellow wire with a red stripe on it. It goes from the key switch and splits before going in the throttle. The top connection on micro switch is for starting the boat. There was the problem , it was a little corroded and some wire exposed not sure how it became exposed. After cleaning it lightly it started right up and then I tried to move all wires and tried to blow the fuse again. To OUR success it have not blown fuse since. I just electrical taped for now because I had people coming on the boat. I did get the micro switch just in case it does it again. it was a couple of bucks :) Thanks for every ones help, I know my boat well now. It took awhile to find but well worth the knowledge I received on my boat. I consider myself a professional now. Lol just kidding Divide and Conquer Boat runs awesome now since I checked every thing on it and cleaned every connection. Thanks again Mr Ed
 
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