HELP! Power loss to Trim/Tilt and Engine Start

[iauctionexpress]

Hi,<br />Saw another post describing exactly this problem. Fortunately for him the problem mysteriously went away, so nobody contributed anything to the post.<br /><br />Here is post I made on the Nitro Owners site. I need all the help I can get <br /><br />Looking for some input on a problem I have and will try to explain it the best I can. I would not make a good mechanic and its my first boat(98' Nitro LXS Mercury Force 120), so I apologize for my lack of terminology. Boat is going to shop on Tuesday for checkup, but this is bugging me and I want to maybe get an idea of what is going on here before Tuesday. <br /><br />Here goes....<br /><br />Hooked all positive and negative leads off motor and accessories to battery. The battery is fully charged. Tested lights, bilge pump, horn, etc. everything here is fine. Tested 2 trim/tilt points, up/down button on front bow and up/down switch on gear shifter...nothing is happening. I was told a third trim/tilt point should be on the motor, but I have yet to find it.<br />I wan't to concerned at this point, but then I tried to bump the motor, nothing happens, not even a hint of a start came from the motor. Now I am real concerned so I start tracing wires, looking at fuses, etc. <br />Located 20Amp fuse on side of motor, it is good. <br />Used a voltage tester and showing 12v going into starter.<br />I traced the trim/tilt motor wiring(1 blue and 1 green) into what I believe are two relays. The two red wires also going into the relays are coming of the positive terminal on the starter. Pull relays apart and verified voltage coming across the contact parts of the red wires.<br /><br />This is as far as I went. Pretty much a dummy here being curious.<br /><br />Have I given you anything here to help you all give me some input? The problem to me seems to be electrical. Is it odd that I'm not able to trim/tilt or get a single crank from the engine, and is it definately related? I sure hope someone out there with maintenance background or even someone who ran into this problem can relate any info to me. It would be very much appreciated.<br /><br />Thanks,<br />William Johnson<br />iAuctionExpress.com

 

[roscoe]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Hmmm.<br />Your description of the wiring sounds normal.<br />Sounds like a ground wire problem.<br />Check connections, starter, solenoid, make sure all are clean and tight, make sure battery connection is wrench tight. Trace the neg battery cable back to theengine and make sure it is tight.<br />Check wiring harness plugs to make sure they are tight.<br /><br />Can you tell if the choke is activating when you push in on the key? You should be able to hear a faint click from the carb area, may need to remove engine cowl to hear it.

 

[iauctionexpress]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Ok,<br />Checked connection to starter, solenoid, everything clean and tight. Grounds are tight, harness plugs are tight. <br /><br />Disconnected the two relays that trim/tilt motor leads to and ran 12v straight to motor. The trim/tilt motor worked flawlessly. Next, jumpered starter bypassing solenoid and the starter engaged the flywheel, no problems there either.<br /><br />I believe the problem is the starter solenoid. Getting 12.6 V to it, but getting nothing out of it to the starter with key engaged.<br /><br />Now the question that has been bugging me since this began is how in the world is a bad starter solenoid responsible for trim/tilt problems also? The marina here is town, not a mercury dealer, told me the trim/tilt and start should be independent. I have my doubts since I have read a few other posts similiar to mine.<br /><br />William

 

[roscoe]

Re: HELP! Power loss to Trim/Tilt and Engine Start

TnT is separate from starting circuit.<br /><br />Perhaps your ignition switch is not sending a signal to the solenoid.<br />I would examine the wiring harness, all the way to the helm and ignition switch. Check for power at the ignition switch too.

 

[iauctionexpress]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Hi,<br />One last question for anyone who might now. I am still checking some things. After looking through and checking harnesses I came across something of concern. In about the about same location as the starter solenoid but on the opposite side is what looks like some sort of box approx. 3x3 with a couple of yellow and red wires going into it, about two each. Several wires in this area along with the yellows and reds are joined together individually with a male/female connector, connection point is covered with clear plastic protector. One of the yellow wires that leads to this box is charred(black). The clear plastic is melted. It is the only one like this. Question...what is this box and its purpose? Motor is a 120 Mercury Force 1998.<br /><br />The boat is going to the marina for service but I was curious what this box was before I take it in.<br /><br />thanks,<br />William

 

[roscoe]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Sounds like you found the problem.<br />Small box is the voltage rectifier.<br />Should have 2 yellow wires coming from the stator, a grey wire going to the tach, and a red wire that connects to the starter solenoid.<br /><br />Sounds like the rectifier failed and caused the yellow wire to burn. Hopefully the damage is limited to the rectifier ($140 for genuine Merc part, cheaper if aftermarket), and hopefully the stator ($200) is all right.<br /><br />Looks like you might have this figured out before you take it into the shop.

 

[roscoe]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Sounds like you found the problem.<br />Small box is the voltage rectifier.<br />Should have 2 yellow wires coming from the stator, a grey wire going to the tach, and a red wire that connects to the starter solenoid.<br /><br />Sounds like the rectifier failed and caused the yellow wire to burn. Hopefully the damage is limited to the rectifier ($140 for genuine Merc part, cheaper if aftermarket), and hopefully the stator ($200) is all right.<br /><br />Looks like you might have this figured out before you take it into the shop. <br /><br />Let us know the final diagnosis and cure.

 

[iauctionexpress]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Thanks for the reply. Even though I am out some bucks probably, I do feel better now that I am getting somewhere in identifying the problem. I do have one other question. Lets say the rectifier and/or stator is bad, what exacty do they do that would cause the motor not to crank and the trim/tilt motor not work. Told you I'm pretty dumb when it comes to these things.<br /><br />William

 

[roscoe]

Re: HELP! Power loss to Trim/Tilt and Engine Start

Not exactly sure but....<br />Since the red wire from the rectifier is connected to the starter, if there is a short to ground in the rectifier, it may also be shorting the starter signal, so that the solenoid will not kick in. Just my thinking. The shop will have to diagnose and confirm.<br /><br />Why the yellow wire burned is the true question.<br /><br />I wonder if the starter would engage if the red wire were disconnected?