1991 Mercruiser Neutral Safety Switch

[NYGiants]

I have a 1991 mercruiser i/o with a 3.0 inline 4 cyl. someone before me bypassed the neutral safety switch and im trying to figure out how to fix it. Im not totally sure where on the engine its located.

 

[Bt Doctur]

its located in the control box, prevents starting the motor while in gear

 

[NYGiants]

guy bypassed it because he said when you shifted into gear the motor would die. right now the boat will shift into gear and you can feel the cables move but the prop will not engage.

 

[Bt Doctur]

That is called the shift interupter. It allows you to come OUT of gear ,in the water with a load on the prop.
General cause is a bad lower shift cable or corrosion in the shift components

 

[Bt Doctur]

http://www.boatfix.com/merc/Techbk/94/94hsa2.pdf

 

[NYGiants]

What would be my best course of action to diagnose this?

 

[Bt Doctur]

If activating on land, you need a new lower shift cable

 

[NYGiants]

I feel the shift but the engine will not engage. I was told its the neutral safety that was bypassed. guy thought he knew more than he did. The prop engages and I cant turn it by hand one way. the prop does not spin under power whatsoever

 

[Bt Doctur]

OK, now that something different Are we on land?
check your messages

 

[NYGiants]

I gave you a call. feel free to give me a call back anytime tonight. I have a feeling its related to crappy work done to my boat.

 

[NYGiants]

Heres an overview of my problems and timeline.

- Bought the boat non running, it had sat all of last summer.

- Got it running in the fall just had a dirty carb

- Took it out in the spring had issues with it cutting out the first time i took it out, but after it warmed up and ran some gas thru it I had no problems.

-Took it out one day and the motor starts lagging, boat falls off plane and dies. Restart motor and the boat dies whenever i shift into gear, get towed in.

-Guy looks at it tells me its the neutral safety switch (points to what i now realize is the shift interupter switch) and bypasses it for me.

-Tilt trim switch randomly goes out and when i bypass the solenoids i get power.

- Now i shift the motor into gear, feel the cables engage and get nothing. Note this is all on land.

 

[Bondo]

Now i shift the motor into gear, feel the cables engage and get nothing. Note this is all on land.

Ayuh,..... The Motor Runs,.... The Drive is shifted,....

Has the interupter switch been hooked back up,..??

When ya say ya shift the motor, are the cables movin' at the switch plate,..??

Pull the lower cable off the switch plate, 'n manually push, 'n pull it,....
Does it shift,..??

 

[Bt Doctur]

Was the drive serviced and filled with oil?

 

[NYGiants]

When i shift it into forward the shifter needs to go pretty far forward before it engages. i hear a clicking noise when i turn it clockwise and the prop is locked when i turn it counter clockwise. cable out of adjustment?

 

[Bt Doctur]

No, that is correct for being in fwd gear.In rev just the opposite is true

 

[NYGiants]

and regarding the drive, i havent done any maintenance to it since i bought it.

 

[NYGiants]

tried adjusting the cables and I believe I had it all correct. I got nothing. When i tried to shift the lower unit cable by hand I can lock the motor in gear but only when its not running. If its running I get no where. Someone suggested its the dogs fork in the drive?