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Solenoid problem?

Discussion in 'Boats and Motors' started by athensfishin', Jun 18, 2007.

  1. athensfishin'

    athensfishin' Fighting the Man

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    I have a 79' mercury 850 and well here is my problem. When I bought it they said the solenoid was bad so I purchased a new solenoid, no big deal like 12 bucks. I put the solenoid in and the ignition will still not work. If i jump it across the solenoid with a screwdriver(old school style) she will start like a top. So I figured the ignition was bad but when I put the tester on the ignition wire post on the solenoid it is getting a charge when I crank the key and the other side is grounded well. The key has to be on the run position before it will start and won't start with the key off so I can only assume the ignition is functioning. So I guess my question is has anyone else had this problem or anyone know what it might be. The only thing left that I can possibly think of is that it's not the exact solenoid for the motor but it's a ford model same voltage size and positioning only thing different is the mounting.
     
  2. zeppelin_2000

    zeppelin_2000 Barberton,Ohio

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    sounds like the solenoid is not grounded the bracket that mounts it must bee grounded or it will not work. you have I take it a solenoid with two large and two small studs you know the two large ones the small ones are "s" for start and "i" for ignition "s" goes to start switch power when in start position. "i" goes to coil for power when cranking if you have the "i" terminal grounded it will crank but not start. the bracket on standard solenoids is the ground side to engage the solenoid.
     

  3. athensfishin'

    athensfishin' Fighting the Man

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    I do see the S and the I the I is connected to the ignition wire but in the wiring diagram that I found here http://www.maxrules.com/oldmercs/Wiring/1966ona/30.gif It shows what would be the S post going around back to the main ground( the double dotted line). I'm not a pro at this sort of thing but at the same time I did not spend alot on the motor and I'd much rather fix this myself than pay a shop an arm and a leg
     
  4. freyedknot

    freyedknot useless poster

    make sure the mounting surface is clean and grounded good.if you can jump it with a screwdriver then you may have gotten a faulty one. have it tested.
     
  5. that was my thought...new ones can be bad!!!
     
  6. zeppelin_2000

    zeppelin_2000 Barberton,Ohio

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    Remember that you are using a automotive solenoid it is not the same as the marine internally . yes yours may be a bad one but try to jump from the main battery terminal side to the s terminal if it cranks solenoid ign switch is bad or misswired. if not may be bad or not grounded. marine solenoids are mostly bolted to wood so they use the I terminal for the ground side of the coil to energize the
    solenoid. automotive doesn't it uses the I terminal to feed the positive side of the coil while cranking and the mounting braket is the ground for the coil internally. try takeing the wire off the "i" terminal and then run a ground to the mounting braket then see if it will trigger.

    look at this page it showes how automotive sol. work

    http://www.chevelles.com/techref/tecref4.html
     
  7. athensfishin'

    athensfishin' Fighting the Man

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    Thanks zep the mounting bolts did need grounded out. Ran a ground wire to the bolt and the key started her right up. Off to hit the water and take it for a test run thanks for the help.