1996 Force 90hp Electrical Power Issue

[mav6759]

I have a 1996 Mercury Force 90hp, I m having a electrical (power) issue. I have 3 solenoids 1 for the starter and 2 for the tilt/trim (one for up and the other for down) Here is where I am pulling my hair out, With everything connected the start motor just spin slowly not engaging the flywheel, the tilt/trim barely moves up or down. When I disconnect either the motor or the til/trim and connect them straight to the battery, everything run fine. I have checked the cables, cleaned the cables, checked for voltage from the battery to the starter solenoid get 12.9, checked the battery 12.9v. I am losing a great deal of power somewhere. Does anyone have any ideas, could this be a starter solenoid issue since all the power is feed through the starter solenoid and then jumped from the starter solenoid to the other 3 solenoids. I have removed each solenoid checked all the wiring and cleaned all the posts.. Please if someone had any idea's I would be thankful..

 

[tommarvin]

1. WOW, where to start, We had a problem where the starter spun slow and barley engaged the flywheel, it was because I put in a two new battery holders and forgot to hook up the ground to the motor to one of the two battery's, I would check that.

2.You have a shorted out wire, or a ground wire is broken off or loose. Check every inch of wire from battery to starter solenoid.

3. there's a video on You-tube that explains perfectly how easy it is to test a solenoid.
4. Is this an ignition switch problem, are you bypassing the I Switch when it tests ok? Our factory service manual shows how to test an ignition switch.
5. Check the circuit breaker and neutral interlock switch ? Good luck, tell us what it was when you find it, please

 

[pnwboat]

Have the battery tested under a load at your local auto parts store.

 

[Nordin]

If you get 12,9V at the starter and it moves slowly there is a starter issue.
I would check the battery as pnwboat suggest and also check the solenoid and the starter.
Take a look at the grounding too. There should be a thick wire from the lower cowl to the engine block.

 

[jerryjerry05]

No Title

You can get 12.9v and still have a bad battery.
Load test.
​The cable could have a weak spot or bad connection??
Clean the starter.Starter pics were from a "good" starter.
The armature pic wouldn't load.
One of the contacts on it was hanging loose.
#3 pic shows the brushes locked in place. Not good.

 

[Jiggz]

All of the above suggestions are worthy to look at. But before going any further and I understand you already cleaned all cable connections,however, you need to disconnect the ground cable from the motor's block, wire brush it or use fine sandpaper to shine the cable terminal and also the mating surface on the engine block. Reconnect and using dielectric grease, grease the entire terminal for corrosion protection. Try again.

 

[tommarvin]

You need a factory service manual,i know where to get it,for a fair price
I am going to send you a private message, tell me if you receive it.

It's has to be a ground that is loose ,broken ,bad contact, check all grounds

 

[mav6759]

I want to thank everyone that commented on my issue...But I have checked everything, I had the starter, batteries, cables, starter solenoid and switches check by a certified marine mechanic still the same issue. The mechanic checked power and all the grounds and he said they were all good. Then he said I had a bad starter solenoid so we changed that out...same issue...So I know its not the starter, starter solenoid, batteries, cables or any of the grounds. The mechanic, could not figure it out, he said he never seen anything like this in the 34 years he has been working on marine motors. But here is the kicker. When I told him that when I connected either the motor cables or the tilt & trim wires directly the batteries, they work fine..(he looked at me like I was crazy) but on the switches the starter motor spins slow and won't engage the flywheel, the tilt & trim moves slowly then molasses. I have no Idea...he claims the switches are good. The only thing I can think of is the harness itself, but he checked that as well..I don't know what it could be any thoughts...

Thanks Mav

 

[tommarvin]

IT"S A WIRE, or a wire going into a connector, give every wire a big yank and twist it.hard.

Don't stop until you find it, you will find it.

 

[pnwboat]

I agree with tommarvin. It sounds like most likely a bad battery cable, or a bad connection on one of the cables that supplies power to the starter. Check both positive and negative cables. Ohm the cables out with a meter.

 

[mav6759]

Thanks guys all your comments, they made me start thinking...(excuse the smoke LOL...) ... I had the back track, back to where everything was good... The last thing I did was put the controls together and I ended up stuffing the wires into the control box. I went out the other day(when it wasn't raining here in VA) and took the control box back off, took it apart and find the purple wire in the control box had gotten caught in the shift handle and it broke..so I'm going to repair that wire,,,(not sure what it does, but its broken..tomorrow it suppose to be 70 degrees with no chance of rain so I'm going to be working on the boat all day. And I guess I will be checking all the wiring from the shifter harness as you suggested,,,My problem has to be in the harness coming from the control box...either I have a bad ground, (which I doubt because everything worked great before the control box was mounted,,, I'm more in cline to believe when the purple wire broke it shorted itself to the control box or it shorted something out, maybe the switch itself.. Thanks mav

 

[tommarvin]

Looks like the next round of drinks for the forum is on you mav6759
Happy ,safe ,boating

 

[mav6759]

Ok, first off I want to thank everyone for giving me all the help, the first round is on me....I found my problem, after doing some back tracking. I was looking for a GOOD ground to ground my battery cable. I thought the best ground would be, one of the four bolts that holds the power head to lower unit. BOY, was I wrong, apparently, when mercury/force designed this motor, they put 1/2 inch rubber insulators (for motor vibration) with a metal tube in the middle, where the bolts that hold the power head to the lower cowling go throw. I pulled one of the bolts thinking it would make a great ground. Boy was I wrong, the battery cable was grounding to the little metal tube in rubber. I removed the cable and grounded it to the starter, everything works great.

Thanks so much everyone, just don't make the same mistake I made,

Mav

 

[Simple_Man]

Thanks for the update