alpha one gen 2 interupt switch

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Feb 6, 2023
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Hello, I have a 2007 boat with mercruiser 3.0. the cable all look good, and the switch works if I trip it by hand. But, moving the shifter to move the cables, does not activate the switch. I see posts saying their engine dies etc, but none on the switch not activating. Again the switch seems good, its the cable doesnt move it. I'm not sure how its supposed to move it, and what isnt working. Cables look and seem in good shape. Maybe I'll try to get pics later.

Chris
 

Scott06

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Hello, I have a 2007 boat with mercruiser 3.0. the cable all look good, and the switch works if I trip it by hand. But, moving the shifter to move the cables, does not activate the switch. I see posts saying their engine dies etc, but none on the switch not activating. Again the switch seems good, its the cable doesnt move it. I'm not sure how its supposed to move it, and what isnt working. Cables look and seem in good shape. Maybe I'll try to get pics later.

Chris
Is this on land or in the water? the switch will not trip on land unless the cable is bad... If you disconnect the lower shift cable from shift plate should move very easily with two fingers...
 
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Is this on land or in the water? the switch will not trip on land unless the cable is bad... If you disconnect the lower shift cable from shift plate should move very easily with two fingers...
It is on land. Wondering how it doesn't move on land but does water ? I guess I'll have to bring it to the dock and give it a try later. Thank you for the info !
 

dubs283

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Jul 27, 2005
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Wondering how it doesn't move on land but does water ?
The design if the clutch in the gearcase and linkage/cable allows for the load on the prop when spinning to force the v spring up/down depending on shift direction to trigger the interrupt switch.

On land there is no load on the prop when in gear therefore no force on the linkage/cable to move the v spring assembly. If the v spring assembly does move on land when shifting that is an indication of a worn/sticky lower cable. Common occurrence on alphas in need of maintenance
 
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The design if the clutch in the gearcase and linkage/cable allows for the load on the prop when spinning to force the v spring up/down depending on shift direction to trigger the interrupt switch.

On land there is no load on the prop when in gear therefore no force on the linkage/cable to move the v spring assembly. If the v spring assembly does move on land when shifting that is an indication of a worn/sticky lower cable. Common occurrence on alphas in need of maintenance
Well, it doesn't move on land...so hopefully it'll work properly in the water. Thank you for the help! When I get to try it in the water, I'll update if its all ok or not.
 

Scott06

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The design if the clutch in the gearcase and linkage/cable allows for the load on the prop when spinning to force the v spring up/down depending on shift direction to trigger the interrupt switch.

On land there is no load on the prop when in gear therefore no force on the linkage/cable to move the v spring assembly. If the v spring assembly does move on land when shifting that is an indication of a worn/sticky lower cable. Common occurrence on alphas in need of maintenance
Exactly. engagement teeth are back cut so they won't release in the water unless load is removed by momentarily cutting ignition
Well, it doesn't move on land...so hopefully it'll work properly in the water. Thank you for the help! When I get to try it in the water, I'll update if its all ok or not.
I assume you haven't taken this boat out on water yet? Again you can test it by removing lower shift cable, should move with very little effort- two fingers holding it... would be worth getting the factory manuals for the gen 2 outdrive and the engine. They are excellent resources if you will be doing your own work.
 
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Exactly. engagement teeth are back cut so they won't release in the water unless load is removed by momentarily cutting ignition

I assume you haven't taken this boat out on water yet? Again you can test it by removing lower shift cable, should move with very little effort- two fingers holding it... would be worth getting the factory manuals for the gen 2 outdrive and the engine. They are excellent resources if you will be doing your own work.
I get why the interupt switch exists....just was not sure how the linkage moved to activate it. I tried it on land and see that the cable pulls and pushes the shift linkage, but the part that would move the switch doesn't move. I plan to try it in the water soon. The boat had the motor out, I did some of the work and someone else did some of it. Well they broke the connector that goes to the distributor that interupts the ignition. so, it didnt work. The boat didnt want to come out of gear (not a good thing to learn at a public boat dock. lol) I got the new connector and wired it up, seen it does work the interupt by hand....switch works. But was thinking I have another issuse when using the shifter to move the cable didnt activate the switch. But, since thats the way its supposed to work, hopefully all is well and it'll work when its in the water.

Thanks again for all the help :)
 

stresspoint

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depending on what switch you have there is a setting for the location of the switch .
i don't have my manual on hand to post the correct measurement , i think 1/8 inch. one type you bend the metal tab so as the roller is in the correct measurement ,the plastic one you just have to loosen 2 screws wiggle it around till the measurement is correct ,a PIA to get right if the PO of the boat messed with around with it as when i got my boat.
 

Scott06

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I get why the interupt switch exists....just was not sure how the linkage moved to activate it. I tried it on land and see that the cable pulls and pushes the shift linkage, but the part that would move the switch doesn't move. I plan to try it in the water soon. The boat had the motor out, I did some of the work and someone else did some of it. Well they broke the connector that goes to the distributor that interupts the ignition. so, it didnt work. The boat didnt want to come out of gear (not a good thing to learn at a public boat dock. lol) I got the new connector and wired it up, seen it does work the interupt by hand....switch works. But was thinking I have another issuse when using the shifter to move the cable didnt activate the switch. But, since thats the way its supposed to work, hopefully all is well and it'll work when its in the water.

Thanks again for all the help :)
OK that makes sense. If you can make it interrupt by actuating the switch then that's all you can check on land. You can adjust the switch but I'd leave it alone if it was working before someone buggered the wiring..
 
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OK that makes sense. If you can make it interrupt by actuating the switch then that's all you can check on land. You can adjust the switch but I'd leave it alone if it was working before someone buggered the wiring..
Yea, I'm not going to touch it until trying it in the water at this point. If I have time after work today I may try it. Mine is not the type with the metal tab, its a plastic housing with a plastic stub that sticks out of it. Another plastic piece pivots to push it in.

Just looking forward to getting on the water again. Someone had changed the motor before I got the boat, and one time while out in it, the starter dropped to the floor! Both bolts were snapped off in the block. I'm thinking whomever worked on it before snapped one off, and didnt want to deal with it. Then the other broke on me in some kinda rough waters crossing Tampa Bay. I lucked out, I'd shut it off next to the ramp, when I went to start it I found the starter had fallen out. So to get the broken bolts out of the block, I had to pull the motor. I've worked on cars a decent amount, but never on boats and outdrives. Learning some things :)
 

Scott06

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Yea, I'm not going to touch it until trying it in the water at this point. If I have time after work today I may try it. Mine is not the type with the metal tab, its a plastic housing with a plastic stub that sticks out of it. Another plastic piece pivots to push it in.

Just looking forward to getting on the water again. Someone had changed the motor before I got the boat, and one time while out in it, the starter dropped to the floor! Both bolts were snapped off in the block. I'm thinking whomever worked on it before snapped one off, and didnt want to deal with it. Then the other broke on me in some kinda rough waters crossing Tampa Bay. I lucked out, I'd shut it off next to the ramp, when I went to start it I found the starter had fallen out. So to get the broken bolts out of the block, I had to pull the motor. I've worked on cars a decent amount, but never on boats and outdrives. Learning some things :)
check to make sure the engine isn't hydro locking when it shuts off. Never seen one break both bolts off.. may have been over tightened... Wonder if starter was replaced with newer permanent magnet starter which uses slightly shorter bolts ? maybe someone tightened the ell out of them
 
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check to make sure the engine isn't hydro locking when it shuts off. Never seen one break both bolts off.. may have been over tightened... Wonder if starter was replaced with newer permanent magnet starter which uses slightly shorter bolts ? maybe someone tightened the ell out of them
I think whomever did the work busted one. And left it with just the one hanging on insted of going through the work of fixing it. I'd only had the boat out maybe a dozen times when the other bolt let go. I don't think there is any way that both broke that day. I checked the motor out some while it was out. compression test etc. Always ran fine.
 
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