1966 Mercury 950 SS distributor question

[johnny howe]

I have a 1966 Larson All American with a Mercury outboard 950 SS.

My question is :
There are two wires that come out of the distributor , a brown and a white. I replaced my switch box, and now...the motor will only run if the brown wire is not connected to anything. where does this brown wire go and what does it do? and i lost my tachometer too. any help thanks john

 

[Faztbullet]

Re: 1966 Mercury 950 SS carb question

Re: 1966 Mercury 950 SS carb question

It for the breaker points, the set attached to brown wire are shorted shut...

 

[johnny howe]

Re: 1966 Mercury 950 SS carb question

Re: 1966 Mercury 950 SS carb question

What do you mean they are shorted out? the motor seems to run fine,with it disconnected , if i touch it to the post on the switch box , it dies.. where does it go?

 

[Faztbullet]

Re: 1966 Mercury 950 SS carb question

Re: 1966 Mercury 950 SS carb question

There are 2 sets of pionts in distributer housing, the set hooked to brown wire are closed/shorted and is grounding out switchbox. If you swapped switchboxes because of a no spark condition, this was your problem and other switchbox is good.

 

[johnny howe]

Re: 1966 Mercury 950 SS carb question

Re: 1966 Mercury 950 SS carb question

do you need both points sets working? do switchboxes go bad that often? can i just leave the brown wire unattached? and why wont my tach work now? are they connected...thanks for all info john

 

[turtles11756]

Re: 1966 Mercury 950 SS distributor question

doesn't a 950SS have a trigger instead of breaker points ? the brown and white wires go to the terminal on switchbox that connects merc switch on the distributor side of switchbox ?

 

[Faztbullet]

Re: 1966 Mercury 950 SS distributor question

First model runs do not and when switchbox was discontinued they where updated to new Thunderbolt 3 wire trigger...

 

[johnny howe]

Re: 1966 Mercury 950 SS distributor question

the engine seems to run great without the brown wire hooked up. is it just running on three cylinders? do you have to have both sets of points working?

 

[Faztbullet]

Re: 1966 Mercury 950 SS distributor question

As posted earlier yes both need to work and no on the three cylinders . The reason is it affects timing (dwell) of engine. Here is how to repair it as you can leave tower shaft inplace and just remove dist housing to service.

Before disconnecting any wiring, the battery should be disconnected. The
breaker point gap should be set to provide 45 degrees dwell for each set of points. Dwell plate (part number C-91-45510A1) can be used to check the angle that points are closed. The second set of breaker points should open exactly
60 degrees after the first set opens. Breaker point gap will be approximately 0.007. This distributor is not equipped with condensers. It is necessary to temporarily install condensers before checking dwell on some distributor testers. Breaker point spring tension should be 33-37 ounces, measured from curve of breaker arm next to rubbing block.