Neutral Safety Switch

Discussion in 'General Discussion' started by midexp, Sep 21, 2018.

  1. midexp

    midexp Active Member

    133
    Oct 5, 2016
    Harrison Township, Michigan Lake St.Clair
    1999 40' Sundancer
    454 merc
    I intermittently cannot start my Starboard engine (7.4L 1999 with Valvet Drive transmission). Have replaced the ignition switch at the dash and the transmission solenoid switch. I know if the gear shifters are not in neutral, engine will not start. When I have the no start, I wiggle the shifter back and forth and engine will not start until about after about 10 minutes, it will start. And I've heard of this neutral safety switch. Wondering if this is the problem. Where is at located?

    Thanks
     
  2. Captain Allen

    Captain Allen Member

    336
    Feb 2, 2009
    Coastal North Carolina
    370 EC 1994
    454 Mercruisers, straight drives
    I've sold my boat, but the neutral safety switch was on the transmission. One other thing to check is the starter solenoid. I had to replace one on my port engine. It was not "telling" the starter to turn over, intermittently.
     
  3. midexp

    midexp Active Member

    133
    Oct 5, 2016
    Harrison Township, Michigan Lake St.Clair
    1999 40' Sundancer
    454 merc
    Thanks. Already replaced starter solenoid.
     
  4. oceanpearl

    oceanpearl Member

    117
    Aug 20, 2008
    Montreal, Quebec, Canada
    400DB Searay 2001
    240 Searay Sundeck 2008
    454 7.4 MPI Horozons
    5.7 Mercruiser 300MPI
    Have you thought of the Slave Solenoid. Picture below.
    It's the thingy with the 2 yellow bolts. It has a cover on top which I removed for the pic.
    Sometimes just cleaning the contacts works. Just a thought.
    upload_2018-9-22_10-15-3.png
     
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  5. oceanpearl

    oceanpearl Member

    117
    Aug 20, 2008
    Montreal, Quebec, Canada
    400DB Searay 2001
    240 Searay Sundeck 2008
    454 7.4 MPI Horozons
    5.7 Mercruiser 300MPI
    Going to the boat today. Will take a pic of the neutral switch and post it.
     
  6. The Bill Collector

    The Bill Collector Well-Known Member SILVER Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    My neutral safety switch is located at the shifter...
     
  7. oceanpearl

    oceanpearl Member

    117
    Aug 20, 2008
    Montreal, Quebec, Canada
    400DB Searay 2001
    240 Searay Sundeck 2008
    454 7.4 MPI Horozons
    5.7 Mercruiser 300MPI
    This is the mercruiser neutral switch on a 7.4 454 engine. It is located behind the transmission. Hope this helps. The cost is around $50.00.
    Good luck!!!!
     

    Attached Files:

    Ezsteps likes this.
  8. midexp

    midexp Active Member

    133
    Oct 5, 2016
    Harrison Township, Michigan Lake St.Clair
    1999 40' Sundancer
    454 merc
    Yes replaced that and the switch on the dash.
    Thanks
     
  9. midexp

    midexp Active Member

    133
    Oct 5, 2016
    Harrison Township, Michigan Lake St.Clair
    1999 40' Sundancer
    454 merc
    It's kind of hard seeing where your switch is at on the trans. I have basically the same switch located right next to the shift lever that the cable is attached to. But my engine owners manual calls this a temperature switch. And it says it needs to get removed and replaced by a pressure gauge to check the trans pressure. If this was both the temperature and neutral switch, how could you start the engine and check the trans pressure with the neutral safety switch out?

    I'd really like to learn more of this switch. Hate to drop $50 on a guess.

    Thanks
     
  10. oceanpearl

    oceanpearl Member

    117
    Aug 20, 2008
    Montreal, Quebec, Canada
    400DB Searay 2001
    240 Searay Sundeck 2008
    454 7.4 MPI Horozons
    5.7 Mercruiser 300MPI
  11. midexp

    midexp Active Member

    133
    Oct 5, 2016
    Harrison Township, Michigan Lake St.Clair
    1999 40' Sundancer
    454 merc
  12. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
  13. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
  14. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
  15. SeadawgVB

    SeadawgVB Active Member

    206
    Jul 8, 2013
    Tidewater Virginia
    '03 Sundancer 360
    Twin 8.1s with V-drives
    9 times out of 10 it is the slave solenoid. If you have replaced it, I would check to make sure there is a good ground. A lot of time corrosion will form under the negative lead.
    The neutral switch can be easily tested with a cheap volt / ohm meter IF you can easily reach it.
     
  16. oceanpearl

    oceanpearl Member

    117
    Aug 20, 2008
    Montreal, Quebec, Canada
    400DB Searay 2001
    240 Searay Sundeck 2008
    454 7.4 MPI Horozons
    5.7 Mercruiser 300MPI
    Can you explain how to read the voltmeter for the neutral switch. I presume you set it on OHM's but at what setting and what should the reading be.
    Thanks in advance.
     
  17. Espos4

    Espos4 Active Member

    596
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Set it to ohms and look for continuity to come and go as you shift between neutral and into gear.

    Basically, zero ohms is continuity and open or infinite is an open circuit.
     
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  18. SeadawgVB

    SeadawgVB Active Member

    206
    Jul 8, 2013
    Tidewater Virginia
    '03 Sundancer 360
    Twin 8.1s with V-drives
    What he said... Set you meter to ohms. With the boat powered off, put one lead on each of the screws. Have a helper move the shift lever in and out of neutral. The meter should jump from about zero ohms (good continuity) to near infinity ohms (no continuity).
     
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  19. HardHead

    HardHead New Member

    27
    Jan 9, 2015
    Sue Creek Maryland
    1996 Sea Ray 370 Sundancer
    Previous boats:270 Sea Ray, 230 Sea Ray,190 Wellcraft,
    24' Trojan
    Twin 454 Mercruiser Inboards
    Once you have located the neutral safety switch. which is on the top of the transmission with 2 wires running to it. If you remove the 2 wires create a jumper wire to connect the 2 wires. Put the shifter in neutral and see if it starts. If it does it's most likely the neutral safety switch. Or it could still be in the linkage to the shifter that is misaligned at the transmission.
    Good luck
     
    Mac-Daddy-Minnesota likes this.
  20. oceanpearl

    oceanpearl Member

    117
    Aug 20, 2008
    Montreal, Quebec, Canada
    400DB Searay 2001
    240 Searay Sundeck 2008
    454 7.4 MPI Horozons
    5.7 Mercruiser 300MPI
    If I am not mistaken, if you jump the 2 wires and start the engine the boat will go into gear immediately. That is the purpose of the neutral safety switch!!
    Be prepared to shut the engine down.
     

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