1985 Mercury user 120 stalling issue

[FredCombs]

Hello all. Trying to narrow down an intermittent stalling issue on my 1985 mercruiser 120. It is on a houseboat and idles fine all day with the exception of this symptom. When docking there is a lot of shifting into reverse, neutral, forward etc. every once in awhile it will die when being put into gear while trying to get into the slip. Starts back fine but sky repeated shifting will cause it to stall going into forward. My first guess would be the shift interrupt switch? I’m going to check the cables when I am at the boat this weekend but wanted to see if anyone else has dealt with a similar issue

 

[bondo]

Ayuh,...... I think yer headed the right way,....

If it is the switch, that's a symptom of the lower shift cable gettin' worn out,....

 

[woodbender]

I have the same engine a 1983 120 alfa 1.

It's very frustrating when she quits going into forward. (mine was sticking in reverse also. Cable adjustment fixed that.)

Thinking it was a fuel issue causing the stalling going into forward, I thought the slower I put her into gear the better.

I found this video which explains about how the gears and interrupt switch work together.

At the end of the video, he suggests shifting into and out of gear very positively, not slowly. He demonstrates how quickly to shift into gear - much more quickly than I have been shifting and certainly not babying it into gear. Shifting slowly gives the switch time to kill the engine.

Just a newbie's $.02. you might not have thought of. It was certainly new info and counter intuitive to me.