Please explain the functionality of the 2 switches within the port side temp switch.

[D0T-C0M]

As I understand the port side temp switch on my 1995 130HP Johnson outboard has 2 switches in it. One brown wire switch that closes to ground @ 240 F that I am assuming is the overtemp protection, and the white/black wire switch that closes @ 105 F. What is the white/black wire switch used for? Is it used for starting only? On my engine the switch is disconnected because the switch was determined as being faulty by the previous owner, (he said the engine would skip bad not sure about that but I'll get it testing correctly). What happens to the motor when this white/black wire is disconnected? Does the timing change, will the engine run rich and use more fuel? I don't know if I am correct but I'm thinking that if you wanted to disable the white/black wire switch, the wire on the motor side should have instead been grounded to simulate the engine at normal operating temperature. right? My engine runs a little rough at idle and very low throttle but works smooth at 1/4 to WOT. I am wondering if this could be the cause.

I have a service manual on order so I should be able to go through my tuning with a fine toothed comb. I should receive it soon but maybe someone could thoroughly explain the function of this white/black wire switch in the meantime.

Thanks in advance.

 

[Chris1956]

Re: Please explain the functionality of the 2 switches within the port side temp swit

That sounds like the Quickstart wire. When the motor is cold, the temp sensor sends a signal (forget if open or closed is the signal) to the powerpack to increase idle timing to warm the motor up. The service manual will give the test procedure, as I do not remember.

BTW - replacement of that switch is in the $80 range. That I remember!

 

[D0T-C0M]

Re: Please explain the functionality of the 2 switches within the port side temp swit

Thanks for the quick reply.

The switch closes over 105f so with the switch always disconnected then the quick start is always on. What happens when the quick start is on? Does the choke solenoid stay on and introduce more fuel or is it only the timing that changes? Also does the advance or retard during this quick start mode? I was out on the weekend and as well as the rough idling I find the engine used a lot of gas. I know 2 stroke 130HP engines use a lot of fuel but if this quick start is always on maybe I'm using more fuel than normal.

 

[Chris1956]

Re: Please explain the functionality of the 2 switches within the port side temp swit

Quickstart will advance the ign timing a few degreed, when the RPM is below 1000. So once you put it into gear and advance the throttle, the quickstart will shut off. On my Johnny 150HP motor, when the motor is warming up in Quickstart mode, it runs rough and will bang into gear. The enrichener is only activated when you hit choke button or push key in to choke.