Shift interrupt

ponchoman

Petty Officer 3rd Class
Joined
Aug 22, 2011
Messages
91
1993 mercruiser 4.3 alpha 1, got the boat out of service and its a real dog to get out of gear forward and reverse. The shifter feels stiff and it keeps on in gear when in neutral. Just had the lower shift cable replaced. Is it something I should adjust, or back to the shop? Is it typical for shifter to be stiff when the interrupt is not working? Thanks!
 
Joined
Mar 27, 2010
Messages
3,008
Re: Shift interrupt

Your interruptor is not working, it will be extremely tough to shift back to neutral without the interruptor....... this is WHILE IN THE WATER.

on land on the trailer the interruptor will not operate unless something's wrong. I am assuming you're referring to in the water.

manually move the interruptor off center either way and see if it stalls the engine, the wires may be disconnected.
 

ponchoman

Petty Officer 3rd Class
Joined
Aug 22, 2011
Messages
91
Re: Shift interrupt

I had the boat in neutral and toggled the switch, no change. All connections seem good.
 

ponchoman

Petty Officer 3rd Class
Joined
Aug 22, 2011
Messages
91
Re: Shift interrupt

Just went out and jumped the switch wires, boat died. Circuit seems good. When i wiggled the switch it started to work but it had to be all the way depressed.
 
Joined
Mar 27, 2010
Messages
3,008
Re: Shift interrupt

The black wire on the interruptor switch goes to ground.
The gray wire on the interruptor rust to a terminal block then turns into a White/Green wire which runs to the distributor.

Test the gray wire on the terminal block for continuity to ground using a digital multi meter when the switch is pressed in. It should beep.

If you jump the gray and black wires on the terminal block you bypass the shift interruptor switch and the engine should die. IF it doesn't you have an issue with a shorted wire or lack of ground.
 

ponchoman

Petty Officer 3rd Class
Joined
Aug 22, 2011
Messages
91
Re: Shift interrupt

Yeah the switch is the issue. How much they go for? I see whole shift plates and just the switches by themselves on the net. $35-$175 lol
 
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