Help! Need (old) Throttle Interruptor Switch

[country_bumpkin]

I bought an old (1986) 20' runabout 2 years ago. It has a mercruiser engine (says 488 on valve cover), an inline 4 cylinder that had been rebuilt. She runs strong, and smooth.

Last week she just died in the middle of the lake. No spark. I traced the problem to a throttle/shift interuptor switch that just finally went kaput.

It is a very simple switch, and looks like it should cost $5-$10. BUT they don't make them anymore so I am told I need to replace the whole assembley (very costly)

Anyone know where I could get one of these old switches? New or used, I don't care.

If not, is replacing the throttle plate something I should attempt on my own?

I am very mechanically inclined, but all those cables, linkages, and adjustments to the throttle and outdrive have me intimidated.

Thanks in advance for your advice,

Country

 

[Haut Medoc]

Re: Help! Need (old) Throttle Interruptor Switch

Ebay......
There is no need to replace the whole shift plate....
That said, that switch is normally open, not closed.....
If the roller is not returning to the center of the detent, I would suspect a bad lower shift cable.......
How exactly did you determine that it is the switch, & not a bad lower shift cable?
Oh, & have you lubricated the pivot points on the shift plate recently?.......​

 

[country_bumpkin]

Re: Help! Need (old) Throttle Interruptor Switch

Ebay......
There is no need to replace the whole shift plate....
That said, that switch is normally open, not closed.....
If the roller is not returning to the center of the detent, I would suspect a bad lower shift cable.......
How exactly did you determine that it is the switch, & not a bad lower shift cable?
Oh, & have you lubricated the pivot points on the shift plate recently?.......​

Thanks for the response.

The roller is in the correct position at the correct time.

The wire comming out of the switch was very loose, swimming around in the switch housing actually. when I disconected all the leads and by passed it the engine jumped to life.

The contact was so loose inside the housing it closed the circuit.

I looked on ebay, no luck. I would be willing to pay a premium for this to avoid the other work!

 

[Haut Medoc]

Re: Help! Need (old) Throttle Interruptor Switch

You will just have to keep looking........http://cgi.ebay.com/ebaymotors/Merc...35404QQrdZ1QQsspagenameZWDVW#ebayphotohosting

 

[country_bumpkin]

Re: Help! Need (old) Throttle Interruptor Switch

http://cgi.ebay.com/ebaymotors/Merc...35404QQrdZ1QQsspagenameZWDVW#ebayphotohosting

I saw that!

In the lower right hand corner of that picture, it does look like the switch I'm talking about. I don't need the whole assembly.

What do you think? I'd be willing to pay the 30 bucks or so just for the switch.

 

[Haut Medoc]

Re: Help! Need (old) Throttle Interruptor Switch

If it looks right, it is worth a shot....
Who knows if it is good.....
I'd roll the dice.......
​

 

[country_bumpkin]

Re: Help! Need (old) Throttle Interruptor Switch

If it looks right, it is worth a shot....
Who knows if it is good.....
I'd roll the dice.......
​

I think I will.

Thanks for your help! I will let you know if it works out!

Country

 

[UNCC Grad]

Re: Help! Need (old) Throttle Interruptor Switch

I did the same thing recently. I only needed the switch but bought the entire assembly used on Ebay...it worked perfectly.

 

[country_bumpkin]

Re: Help! Need (old) Throttle Interruptor Switch

I did the same thing recently. I only needed the switch but bought the entire assembly used on Ebay...it worked perfectly.

Did you look at the pic in the link?

Do you think it will work?

 

[UNCC Grad]

Re: Help! Need (old) Throttle Interruptor Switch

I can't tell much in the picture, but if it is from the same motor and era it should work.

 

[country_bumpkin]

Re: Help! Need (old) Throttle Interruptor Switch

Ebay......
There is no need to replace the whole shift plate....
That said, that switch is normally open, not closed.....
If the roller is not returning to the center of the detent, I would suspect a bad lower shift cable.......
How exactly did you determine that it is the switch, & not a bad lower shift cable?
Oh, & have you lubricated the pivot points on the shift plate recently?.......​

Okay, I replaced the switch, but now I'm thinking shift cable.

She fired up like a champ yesterday. Let her warm up then took the kids out to do some skiing on a gorgeous Memorial Day. Motoring out into the lake at about 1/3 throttle she was purring. When I pulled my daughter up on her skis I eased it just past 1/2 and it died. Luckily not too far from the launch ramp and luckily the Marine Patrol was willing to tow us back.

On the trailer I was looking at the shift plate and switch, and noticed that the switch arm rolls up on the cam just past half throttle. Do I just need to adjust the cables?

Two things concern me. Why wouldn't the boat restart afterwards? Even after I bypassed the switch completely? (it did this the first time, wouldn't restart, but when I bypassed the switch on land the next day she started immediately).

The other thing is how did it get out of adjusment? Just time and wear? Or is it a lubrication issue? The engine was replace 2 years ago and both cables and plate still look brand new.

I have read the thread discussing how the cables and switch interact. Should I go through the steps listed and try and adjust them?

Thanks for any suggestions.

 

[Haut Medoc]

Re: Help! Need (old) Throttle Interruptor Switch

You can try to adjust the cable, but how old is it?...
They don't last forever.....​