Shift interrupt question

[ugbandtulsa]

Hellooooooo, the Don S. fan club has a couple questions, lol

**Merc Alpha one, gen 1**

1. Why does the shift interrupt system only work in the water?
2. Why does Mercury not make the old-style roller switches anymore? Has anyone successfully located a direct replacement, with no mods? (Part # and manufacturer please?)
3. Do the replacement plate kits that Merc sells generally fit exactly, with no mods, with exsisting cables?
4. Has anyone successfully opened and repaired a dead switch, or are they plastic welded together?

Thanks!

86 Formula 272, Merc 260's, Alpha ones

 

[Bondo]

Re: Shift interrupt question

1) It Can't sense a Load,........ If there is No Load.......

2) Ask Mercruiser, Haven't heard of anything other than ebay......

3) Don't Know,..... Don will catch that 1.......

4) Haven't seen anything posted on any of the forums that I cruise,.....
Other than that there's Way More people that Destroy their Switches by F---ing with them,.......
Instead of just Replacing their Lower Shift Cable,.....
Which is Usually the Base Issue of their Problems...........

 

[ugbandtulsa]

Re: Shift interrupt question

Thanks for the quick reply.

Could you elaborate on number one a bit, how does it sense a load? I thought the switch lever was depressed when the cam on the shift plate moves past the notches and "roller" on the switch...why would this action differ if the boat was wet or dry? My cables are new, so i know this is not the cause. I have also depressed the switch and tested for continuity....dead switch. But i'm still a little bummed that I can't understand the action of the whole plate/cam/switch thing. You're right, it won't work with no water, but I just can't figure out why not? Actually, if you actuate the assembly manually, the whole thing looks like it won't work anyway, cuz the lower shift cable is not "anchored" to anything on the plate, so how does it actuate the cam/lever, and thus depress the switch???

Personally, I think the entire assembly was designed by aliens.

lol

 

[Ryan00TJ]

Re: Shift interrupt question

Hellooooooo, the Don S. fan club has a couple questions, lol

**Merc Alpha one, gen 1**

1. Why does the shift interrupt system only work in the water?
2. Why does Mercury not make the old-style roller switches anymore? Has anyone successfully located a direct replacement, with no mods? (Part # and manufacturer please?)
3. Do the replacement plate kits that Merc sells generally fit exactly, with no mods, with exsisting cables?
4. Has anyone successfully opened and repaired a dead switch, or are they plastic welded together?

Thanks!

86 Formula 272, Merc 260's, Alpha ones

1. Bondo is correct.
2. It's not made as the newer switch interrupts are electronic. I went to a small marine store and got the last new one they had for $70 in case my original ever dies. I was quoted about $300 for the swap to the new style.
4. Not that I know.


Just keep an eye on Ebay for one. I saw a NIB switch go for $75 not too long ago.

 

[country_bumpkin]

Re: Shift interrupt question

Hellooooooo, the Don S. fan club has a couple questions, lol

**Merc Alpha one, gen 1**

1. Why does the shift interrupt system only work in the water?
2. Why does Mercury not make the old-style roller switches anymore? Has anyone successfully located a direct replacement, with no mods? (Part # and manufacturer please?)
3. Do the replacement plate kits that Merc sells generally fit exactly, with no mods, with exsisting cables?
4. Has anyone successfully opened and repaired a dead switch, or are they plastic welded together?

Thanks!

86 Formula 272, Merc 260's, Alpha ones

Here is a used one for 80+ bucks!!!!!:
http://cgi.ebay.com/ebaymotors/ws/e...RK:MEWA:IT&viewitem=&item=280105399473&rd=1,1



I bought this whole assembly for about 32 bucks and just took the switch off:

http://cgi.ebay.com/ebaymotors/ws/e...RK:MEWN:IT&viewitem=&item=250113248864&rd=1,1

good luck, I'm new and still trying to figure this out too!

 

[bruceb58]

Re: Shift interrupt question

The dog clutch has an angle to them so that when they are engaged, it is harder to seperate them when they are loaded. Therefore, the cable is push/pulling harder when they are under load and causes the interrupt switch to be activated.

 

[Bondo]

Re: Shift interrupt question

the whole thing looks like it won't work anyway, cuz the lower shift cable is not "anchored" to anything on the plate, so how does it actuate the cam/lever, and thus depress the switch???

It's Not anchored because it's the Outer Cable that does the Switch Actuation,.........
The Inner Cable only does the Shifting.........

As noted by Bruce,...... The Gears shift Too Easy for the Switch without the Load.....

 

[Alumarine]

Re: Shift interrupt question

2. Why does Mercury not make the old-style roller switches anymore? Has anyone successfully located a direct replacement, with no mods? (Part # and manufacturer please?)

If you go to an electronics supply shop you should be able to find a roller switch that will work, perhaps with a bit of modification.

I don't think Mercury ever made them - just sourced them.

 

[HT32BSX115]

Re: Shift interrupt question

Alphas and Cobras require interrupting the ignition somehow to reduce the torque momentarily so you can separate the clutch dogs.

The timing must be such that there's cable tension or "push pressure" on the (shift) cable before the ignition is "pulsed" or interrupted allowing the "dogs" to separate. (it's not needed or used to engage them)

You gotta have it or you will have to shut the engine down to get it out of gear or eventually break something forcing it out of gear.

Your only other choice is to get a Bravo (or a Volvo) which uses cone clutches that don't need momentary torque interruption to disengage.


Regards,

Rick

 

[Coors]

Re: Shift interrupt question

The newer style esa doesn't need the switches, $80.

 

[74Silverline]

Re: Shift interrupt question

When my shift interrupt switch went bad I just went and bought a switch from a local electronics manufacturer. I found one that was darn near identical. Only mod I had to do was to drill and tap one little hole. One of the holes in the switch lined up, one didn't . It's been working fine for two years. If I recall, I got two switches and I think it came out to like 10 bucks total.

74Silverline...