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350 crusader starts in gear

newbedford64

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1981 Blackfin 25 combi with twin 350 crusaders (2010 w/370 hrs). The port engine is stuck in forward, stalls when I put it in reverse and starts in gear (forward). The port shift cable moves the shift lever into all 3 positions (same as starboard engine). Based on what I've read I'm thinking it might be the shift interrupter switch. Where exactly is it?
 
Depends upon the gear you have....betting that you have velvet drives, the neutral safety switch is on the opposite side of the gear from the shift lever....you should be able to see the two yellow/red trace wires connected to it....
 
1981 Blackfin 25 combi with twin 350 crusaders (2010 w/370 hrs). The port engine is stuck in forward, stalls when I put it in reverse and starts in gear (forward). The port shift cable moves the shift lever into all 3 positions (same as starboard engine). Based on what I've read I'm thinking it might be the shift interrupter switch. Where exactly is it?

If these are Borg Warner Velvet Drives, you will have a neutral safety switch that prevents starter motor action while the transmission is in either gear.
In other words, the transmission must be in neutral in order to activate the starter motor.

The switch will look similar to this:

shopping






Shift Interrupt or Shift Assist systems are generally found on Dog Clutch stern drives.

If this 1981 boat is equipped with Dog Clutch stern drives, then you will have either the Shift Interrupt or Shift Assist, and your neutral safety switch will most likely be at the throttle/shift units.



More into would be very helpful.


.
 
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It has the Borg Warner Velvet Drives. I found the neutral safety switch & ordered/received a new one. The screws on the new switch are slightly different colors (1 bronze / 1 silver) and I'm hoping the screws on the old switch are bronze / silver. If the old screws are the same color, how do i determine the correct connection since both trace wires are yellow/red?
 
It doesn't matter - just make sure there is one YEL/Red wire connected with each fastener and you will be ok...
 
I replaced the neutral safety switch and nothing changed. It still starts in forward gear, neutral goes forward and reverse stalls. I tried starting it in reverse - it clicked but didn't turn over.
 
What should the voltage read on the switch? Should it be different for each of the terminals? If it's a wiring problem, what gauge wire should I use when I replace them? (Both wires are yellow/red)
Thanks
 
What should the voltage read on the switch? Should it be different for each of the terminals? If it's a wiring problem, what gauge wire should I use when I replace them? (Both wires are yellow/red)
Thanks


You should not see any power at the neutral safety switch until the helm key switch is put into the "Start" position. Even at that, only one yellow/red stripe side will be powered. When the neutral safety switch closes, that's when you would see power at either terminal.

The purpose of the neutral safety switch is to interrupt the S circuit (to the starter motor's solenoid) unless the transmission is in neutral.


And yes, it is very common to see yellow/red stripe used for the S circuit.



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I replaced the neutral safety switch and nothing changed. It still starts in forward gear, neutral goes forward and reverse stalls. I tried starting it in reverse - it clicked but didn't turn over.


To further this...... if the neutral safety switch is still allowing for starter motor engagement while IN Gear, then it may be possible that something within the transmission is not activating the switch properly.


As for the clicking..... if the solenoid is clicking, yet no starter motor action, that would indicate that the solenoid is receiving power.

As for the engine stalling..... that should be un-related to the neutral safety switch.
 
have you checked the trans oil levels and condition?
If the shift lever is in neutral the motor will start , if it goes forward when the lever is in neutral you have a trans problem
 
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It's possible that somebody has altered the wiring on the engine as it left the factory....could have been during the engine installs or because of other reasons...

If the shaft is rotating (in the FWD direction) with the shift lever in neutral, its likely that the clutches are warped....either way, it would be prudent to remove the gear and have a qualified individual go thru it....
 
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