** HELP - 1997 60/45 Mercury Jet 3rd Wiring Harness Fried Lots of Smoke **

[Bails314]

1997 60/45 Mercury Jet. Never had any problems with this motor until about 4 years ago. Beep , Beep, Beep in the Throtle control box. Took it to dealer, they said bad sensor in Oil Float. They replace it. I used this boat maybe 2 hours, no problems. Then, 3 months later, hauled it to the lake, would not start...after further looking into it...the wire harness from the throtle control box, all the way back to inside the engine was completely melted and wires with burnt beyond recognition. While at the lake, I had 3 Ford mechanics "rebuild" a wire harness. Still would not crank. Took it back to the dealer, they said that the "computer" (Control box in the motor) was fried. They replaced it. They said no need to replace the wire harness, the rebuilt one looked fine. Next spring, took the boat out..no problems (but did not run it much)...4 weeks ago, used it again..this time, smoke coming from the Throtle control box...eventually wires fried again, all the way back to the motor...(now I'm on my second wire harness). Nothing else has been connected to the battery, just the pos and neg for the motor. Now, I'm in Tennessee...took it to a repair shop, guy said that the Voltage regulator looked good...he had a wire harness, so on goes the 3rd harness. Said I needed a new Safety Neutral switch....so, this last thursday, make the trip back down to tennessee to fish, and get my boat back. The guy said that he ran the boat for a while, (in a tank..and at idle)...no problems. So, I take the boat out for a quick spin, holding the wire harness checking for heat...nothing ...seems like it's fixed....get the wife in the boat, 1/2 speed to our spot...still no heat coming from wire harness...then, full throtle for about 1/2 mile...turn off the engine, drop the trolling motor to start fishing...wife yells..."Smoke"...once again, smoke coming from the throttle control box and Also from under the motor cover. I go to unhook the battey and Scortch my thumb on the positive post. I mean, the positive post was HOT HOT. So now, I'm screwed..again. This is the 3rd time this has happened, and no one can seem to figure out the problem. I don't know what to do. It seems the problem is coming from a charging somewhere...and that the past two times this has happened, it's after the boat has been full throttle and high rpms. I've put about 600.00 in on this now, and still have electrical problems. Pulling the cover off the motor shows wires burnt down to copper...I just don't know what to do...especially if dealers can't solve the problem.

 

[giericd]

Re: ** HELP - 1997 60/45 Mercury Jet 3rd Wiring Harness Fried Lots of Smoke **

had a similar problem with my '96 60hp, i didnt fry the harness but melted the wires at the starter and at the battery. a few things i found was first get rid of the wing nuts on the battery they are bad news! replace with ss nut/washer and crank them down with a socket! second i would recoment you replace the battery, not fun to drop the $80+ i know but with this type of eletrical issue some thins was arching / shorting out the batt was discharging serious amounts of electricity which could have caused an arch between the plates inside the battery. if that is the case you will go through this as many times as it takes for the batt to finally die. i thought my wing nuts were tight, i have pretty strong hands and cranked them down untill it hurt but it wasnt enough. i noticed while running that between the pos cable and the terminal was sparking like a spark plug, reached back to tighten it and wore the burn mark of a wing nut on my thumb and forefinger for a month (sounded like bacon dropped in to a hot pan when i touched it!). i put on washers/nuts and got a new batt and problem solved, cables are normal temp and the engine runs better too, cured the split second long power cutting out problem i was having. also check to make sure that your shifter is not cutting in to your trim wires in the box, this could verry well be where the short is comming from. good luck