Neutral Safety Switch

midexp

midexp

Active Member
Oct 5, 2016
423
Harrison Township, Michigan Lake St.Clair
Boat Info
1999 40' Sundancer
Engines
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
 
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.
 
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
 
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!!!!
 

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oceanpearl said:
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!!!!
Click to expand...

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
 
midexp said:
Yes replaced that and the switch on the dash.
Thanks
Click to expand...
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.
 
SeadawgVB said:
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.
Click to expand...

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.
 
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.
 
Espos4 said:
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.
Click to expand...

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).
 
midexp said:
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
Click to expand...

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
 
HardHead said:
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
Click to expand...
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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