Evinrude Ocean Pro 175 '98 in slow mode

[Chris1956]

Cat22, the motor is a 12V system. Anything over a few ohms resistance to ground will not therefore trigger the SLOW system, as it is based upon a grounding of the sensors. The sensors need to be a dead short to ground to trigger the SLOW system.

 

[gam101]

Just for the heck of it, try switching your meter to the 200 or 2K ohm setting instead of buzz and see if you get any reading on the tan sensor wires.
I pulled the sensor out of my 94 175 motor and it's just a blind hole so removing the head isn't going to do you any good.

edit: It wouldn't hurt to go even higher on your meters ohm scale and check for a reading, I'm not sure what it would take to trigger slow mode.
Good luck

Ok, I’ve got the left sensor out. Going to test with your suggestion & post here. Appreciate it. Meanwhile there has been an interesting development with the thermostats (see below).

 

[gam101]

Well, both the thermostats it turns out are MIA. I am just as baffled.

 

[racerone]

Have you looked at issues with the HORN itself ??

 

[gam101]

Have you looked at issues with the HORN itself ??

That’s the other part that is also MIA. How I know the overheat sensors are screaming overheat is because the mechanic said when he disconnected them, the OB ran fine. So no more Slow mode.

Other than that, I truly have no indication that the sensors are sending overheat messages.

 

[racerone]

Time to do a complete inspection of wiring on this motor.-----It appears that hap hazard work was done.------Sounds like a " blind creature was looking for a nut " to me.

 

[CatTwentyTwo]

Cat22, the motor is a 12V system. Anything over a few ohms resistance to ground will not therefore trigger the SLOW system, as it is based upon a grounding of the sensors. The sensors need to be a dead short to ground to trigger the SLOW system.

OK thanks Chris, I wasn't sure about that and just wanted to throw it there. It's curious that the sensors are triggering SLOW and yet test out fine.

 

[Chris1956]

All you need to put that motor into the SLOW mode is a short to ground on the white/black temp sensor wire. The white/black wire could have rubbed off the insulation anywhere along it's length. The powerpack could also have issues.

 

[Faztbullet]

All you need to put that motor into the SLOW mode is a short to ground on the white/black temp sensor wire

This is incorrect as the wht/blk is for Quikstart which goes to ground around 90-100 degrees. When either of the tan wires go to ground the alarm/light and SLOW is activated. The motor missing t-stats will cause it to overheat as it goes thru to fast and cannot cool.

 

[gam101]

All you need to put that motor into the SLOW mode is a short to ground on the white/black temp sensor wire. The white/black wire could have rubbed off the insulation anywhere along it's length. The powerpack could also have issues.

Just wanted to add that the power pack is new. Replaced it a month ago. Thanks.

 

[gam101]

This is incorrect as the wht/blk is for Quikstart which goes to ground around 90-100 degrees. When either of the tan wires go to ground the alarm/light and SLOW is activated. The motor missing t-stats will cause it to overheat as it goes thru to fast and cannot cool.

Appreciate that last bit on why absence of thermostats will result in overheat. Planning to buy & place those in.

 

[Chris1956]

My mistake, Fazt is correct on SLOW mode activation wire color.

 

[gam101]

Question please; Would the tell-tale flow be impacted (reduced or increased) once the thermostats are replaced?

I want to also share that I spoke with a different mechanic & his opinion was that the absence of thermostats keeps the water constantly flowing through the motor & actually helps in cooling. I think that's flawed thinking because it defeats the purpose of the thermostats.

 

[racerone]

??----Not sure why folks think that " fast flowing " water can not cool.

 

[Faztbullet]

Would the tell-tale flow be impacted (reduced or increased) once the thermostats are replaced?

No as this is water pump indicator and water comes off exhaust before t-stats...Just cause it pees good does not mean it cooling on a Johnrude.

??----Not sure why folks think that " fast flowing " water can not cool.

On loopers(Merc and Johnrude) the water flow needs a restriction to slow it down so it has better heat transfer. The way the 60 degree t-stat/popoff is designed the t-stats control cooling below 2500rpm and pops off over that, the t-stat housing restricts the water flow at WOT. That why we install 3/8 washer in Mercs when t-stat is removed....

 

[gam101]

No as this is water pump indicator and water comes off exhaust before t-stats...Just cause it pees good does not mean it cooling on a Johnrude.


On loopers(Merc and Johnrude) the water flow needs a restriction to slow it down so it has better heat transfer. The way the 60 degree t-stat/popoff is designed the t-stats control cooling below 2500rpm and pops off over that, the t-stat housing restricts the water flow at WOT. That why we install 3/8 washer in Mercs when t-stat is removed....

Once again Fazt, indebted to you for your detailed explanation. Thank you.

 

[racerone]

?---Need to slow it down so it does not " overcool " the motor ?