mercruiser 470 shift interrupter switch

[xanadu30]

I have a 1980 Silverline 17' boat with a merc. 470. The shift mechanism that trips the shift interrupt switch is way off kilter, and I've been trying to adjust things for two weeks now with no fix. Once I adjust one thing, the other is off, etc. My main question is however; why such an extravegant mechanical system for such a simple switch? Couldn't one simply install a momentary switch circuit at the shifter itself to perform the same function? Am I missing something here? Seems to me that a simple momentary engine cut-off switch wired in conjunction with the shifter (from gear to neutural) would accomplish the same task, without having to rely on cable tension, etc. What do you think?

 

[Boatin Bob]

Re: mercruiser 470 shift interrupter switch

OMC takes it one step further by putting a electronic module into the circuit with the switch (ESA Module) but here is a site that has a pretty good Merc switch adjustment procedure that may just help you. Merc Interrupt Switch Adjustment

 

[xanadu30]

Re: mercruiser 470 shift interrupter switch

So, do you think it would work if I install a simple circuit myself? I mean, is there any other function of that mechanical pivot arm other than to activate the engine cut-off switch?

 

[FreeBeeTony]

Re: mercruiser 470 shift interrupter switch

Can the adjustment be made w/o the outdrive installed?

 

[Boatin Bob]

Re: mercruiser 470 shift interrupter switch

No the arm is to activate the switch, the circuit that OMC uses just causes the engine to stumble rather than cut right out like the Merc if the switch is activated too long.<br /><br />Tony...have only played with Cobra's but the drive has to be on and you put in gear and spin the prop to make sure everything is engaged.

 

[xanadu30]

Re: mercruiser 470 shift interrupter switch

OK, what I'm saying though is, what if I bypass the arm and switch completely,(simply disable the original interrupter switch) and hook up a momentary kill switch to activate when the throttle is returning from gear to neutral. Would that not accomplish the same result? (allowing the gears to come back to neutral position)

 

[Boatin Bob]

Re: mercruiser 470 shift interrupter switch

Theoretically yes it would accomplish the same thing. When in gear and under load (prop on and in the water) the gears are tightly linked together, momentarily stalling the engine takes the load off the gears making them very easy to separate. The timing of the interrupt switch is critical, making at the wrong time won't help, making too long will most likely stall the engine. Your best bet is to get the arm switch asm adjusted and working correctly.

 

[FreeBeeTony]

Re: mercruiser 470 shift interrupter switch

I am new to this switch and will soon be going through the same problem...........If I understand this correctly the switch only comes into effect when shifting from fwd/rev into neutral, not from neutral into gear. Is this correct? If so then it cannot be adjusted w/o the outdrive installed. I was checking the operation of the switch w/o the outdrive installed and it didn't seem to be working properly. Is this because there isn't any load on the lower cable?

 

[Boatin Bob]

Re: mercruiser 470 shift interrupter switch

Yes Tony...got to have the drive on, there is no resistance without the drive on and transom shift cable connected

 

[wanna go fishing]

Re: mercruiser 470 shift interrupter switch

We have a 470 mercruiser on a 1979 bayliner 23'. When we have the boat out of the water, we hook it up to the muffs and a hose the shifter gear works good, it will change into foward, nuetrel and reverse. Then as soon as we put the boat into the water we try to change gears but it will just get stuck. we have to shut off the engine to get it out of gear.does anyone have an answer to this?:facepalm:

 

[Eric 3.7LX Alpha 1]

Re: mercruiser 470 shift interrupter switch

We have a 470 mercruiser on a 1979 bayliner 23'. When we have the boat out of the water, we hook it up to the muffs and a hose the shifter gear works good, it will change into foward, nuetrel and reverse. Then as soon as we put the boat into the water we try to change gears but it will just get stuck. we have to shut off the engine to get it out of gear.does anyone have an answer to this?:facepalm:

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