why disc an interrupt switch

johnzonh

johnzonh

Petty Officer 2nd Class
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just in need of some opinion... outside of just plain stupidity...why would you want to disconnect the shift interrupt? the guy I got ours from (alpha one drive/ merc 165) just left the wires hanging. so like a good boy I reconnected things... adjusted cables to specs, lubricated etc. Just wondering ..from all you experienced guys... why anyone would leave it hanging? (the switch tested fine)
 
M

muc

"Retired" Association of Marine Technicians...
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Bad or misadjusted shift cable was killing the engine when he shifted?
 
NHGuy

NHGuy

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You did the right thing. Engineers usually have a reason for things they include in devices.
 
thumpar

thumpar

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It would be pretty hard to shift out of gear without is. Muc is probably right. If the cable was bad or not adjusted correctly it can kill the engine.
 
P

Phreaq

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johnzonh said:
just in need of some opinion... outside of just plain stupidity...why would you want to disconnect the shift interrupt? the guy I got ours from (alpha one drive/ merc 165) just left the wires hanging. so like a good boy I reconnected things... adjusted cables to specs, lubricated etc. Just wondering ..from all you experienced guys... why anyone would leave it hanging? (the switch tested fine)
Click to expand...

Can you post picture of your switch and inner transom please?

Also, is the switch just a simple open close to ground, or is there some kind of load/resistor inline?
 
Eric 3.7LX Alpha 1

Eric 3.7LX Alpha 1

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Worn out lower shift cable causes the switch to engage too long and kills the engine. The easy fix is to disconnect the switch but now shifting is super hard and can even sometimes go from forward right into reverse skipping neutral.

There's a very good chance your cable is worn.
 
johnzonh

johnzonh

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I will be able to post a pic in a few days..I am out on a trip and away from it. thanks for the link it was good info. you guys rock
 
Bt Doctur

Bt Doctur

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Ph, its best to start your own thread with your own problem.
The switch using a points ign or a TB IV electronic ign system supplies a ground to stumble/kill the engine to shift out of gear. considering that switch is NLA
there is a new shift plate from Merc with a new type switch. That one needs a slight rewire to work properly shifting out of gear using a points system or the TB IV system.
Take the power wire off the + side of the coil and run it to 1 wire of the new switch, take the remaining wire from the switch and connect it to the + side of the coil.
You are now interrupting the ign by removing the power to the coil instead of supplying a ground to the coil.
 
achris

achris

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Phreaq said:
While that is a wonderful post, I have read, and read twice again today, it does not help me understand if the circuit needs/has resistance. My switch looks fried, and is too old to buy a replacement.
Click to expand...

No resistance. Just the switch straight to ground. Remember, it's grounding the negative side of the coil (for a points based system). The coil IS the resistance in the circuit. For that circuit it just looks like the points have stayed closed for a long time... In a Thunderbolt IV or V system the switch is grounding one side of the ignition sensor. The current limiting (resistance) is already in the module, so again, no resistor. In a PCM/ECM 555 system the switch is connected directly to a couple of pins on the ECM, and the module just drops half the fuel injectors off... The 10K resistor is there to stop one of the lines 'floating' when the switch is open...

HTH,

Chris......
 
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Phreaq

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OMG I can't believe I mixed that up, Switch was disco'd and looks bad when I got it. Thank you soooooo much achris!!!
Hope I can crack this thing open and rewire it somehow. Cant afford a new shift plate, nor could I do the work right now.
I am disabled and the medications don't help my memory.
Again Thank you so much!

Edit: for the OP: The switch should never be disconnected, however I can get out of gear by pulling to neutral and turn the motor off. Not sure if I should be doing that.
Anyway, I dont want to further clog up this post. I will start a thread for my switch tear down, if needed.

sorry for the hijack
 
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johnzonh

johnzonh

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Jun 11, 2008
Messages
137
sorry this took so long to get back to everyone... my switch is simple ground out. no resistors. I am having upload issues with my pic.
 
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