75 merc OB 1150 starter problems.

[jeramie78]

I jut got ahold of a 75 mercury 115hp outboard. I went to go fire it up to make sure it works ok but the starter spins the wrong way. Its the orignal starter and the cables are on the right posts. If i hook the starter up to jumper cables with positive on the bottom and negative on the top it spins the right way. Soon as i reinstall it into the boat and hook the wires up it spins the wrong way again.

Any ideas?

 

[jhodge]

Re: 75 merc OB 1150 starter problems.

May I ask, how do you know it spins the wrong way? Check polarity of the cable going to the starter via the starter solenoid. That cable should be hooked to the positive post on the battery. Do an ohm test on the cable to be sure they arn't crossed. Do the ohm test with both ends disconnected. The cable from the solenoid should go to the isolated post on the starter and not to the starter case, which is grounded via a cable or thru the starter anchor clamps. Original starter, huh? Was the starter gear recently changed? There clockwise and counterclockwise gears. Was it recently rebuilt?
The timing marks on the flywheel will indicate which is the correct direction for starting. Be careful, hooking up a wrong polarity could cause damage to the electronics. Good luck JH

 

[Chris1956]

Re: 75 merc OB 1150 starter problems.

Ground is the top cable. It connects directly from the starter case to the cowling support. The bottom connection is obviously +12VDC.

If it still spins the wrong way, someone may have reversed the permanent magnet that serves as the field winding.

 

[jeramie78]

Re: 75 merc OB 1150 starter problems.

May I ask, how do you know it spins the wrong way?

Um it isnt engaging like i said above. <shakes head>

I know how a starter works as far as what cables go where and which way it has to spin to engage the motor

The starter is original has not been rebuilt.

The polarity is correct going into the selenoid and out of it.


Now what about this magnet? Please more details.

 

[daveswaves]

Re: 75 merc OB 1150 starter problems.

Um it isnt engaging like i said above. <shakes head>

I know how a starter works as far as what cables go where and which way it has to spin to engage the motor

The starter is original has not been rebuilt.

The polarity is correct going into the selenoid and out of it.


Now what about this magnet? Please more details.

Well, since the starter is original and has not been rebuilt its not the magnet. At the risk of getting another "head shake" are you sure the starter gear is "able" to move up the shaft. You will also notice a warning on the starter that says "do not strike with hard object" is there any chance that someone has hit the starter with a hammer to "free it up". The permanent magnet could be broken.

 

[jeramie78]

Re: 75 merc OB 1150 starter problems.

When i pulled out the starter gear was stuck from coming up like it should. I cleaned it and greased it up. Now it moves freely and works correctly long as its out of the motor and i hook it up directly to the battery with jumper cables. As soon as i hook it all back up to the motor then it startes to spin backwards. There isnt a safety relay somewhere that could be causing it to do this? Like if the motor is already running or something it wont engage or spin the oposite direction? Just a thought.

Ans yes it looks like the starter has been struck by something a few times now that you mention it. Is it easy to pull apart the starter and make sure the magnet is ok?

 

[daveswaves]

Re: 75 merc OB 1150 starter problems.

When i pulled out the starter gear was stuck from coming up like it should. I cleaned it and greased it up. Now it moves freely and works correctly long as its out of the motor and i hook it up directly to the battery with jumper cables. As soon as i hook it all back up to the motor then it startes to spin backwards. There isnt a safety relay somewhere that could be causing it to do this? Like if the motor is already running or something it wont engage or spin the oposite direction? Just a thought.

Ans yes it looks like the starter has been struck by something a few times now that you mention it. Is it easy to pull apart the starter and make sure the magnet is ok?

Its easy to take apart, a little tricky to put back together. There is no safety relay, good idea though. If it turns correctly when out of the engine and incorrectly when it is in the engine there has to be something backwards in the wiring. Its a DC motor. If the magnet is cracked it is possible, but not likely, that it could turn backwards. Usually it would just have low torque.

 

[jeramie78]

Re: 75 merc OB 1150 starter problems.

Well finally got back to working on it. Come to find out after my buddy assured me that all his cables were correct and that he used a test light to make sure .... the battery cables werent connected correctly. The red wire had been stripped for whatever reason from the previous boat owner. So both of us thought its stripped its a neg wire. So we switched the wires and the starter worked properly. Now fo the fun part of replacing the lil "blackbox" lol forgot what it is at this moment. And to make another post on how it tries to fire up but wont stay running even after cleaning the carbs making sure there is spark and that the switch box operates correctly