Evinrude Ocean Pro 175 '98 in slow mode

[gam101]

Greetings fellow sailors!

Off the bat; newbie ALERT! :facepalm:

Need your help/advice please with the following;

A little history: outboard over-heated one day while I was out, and the boat mechanic said the impeller had failed. :blue:

He;

1) Replaced the impeller
2) Replaced the fried powerpack
3) Cleaned the heads and replaced the piston o-rings (apparently the previous owner had used silicone inside the heads)
4) Re-did all six carbs with carb rebuild kits. because it was idling rough.

I took the boat out & it was slow. It would not go fast period, and when I tried to speed-up a little, the outboard would rattle & shake the entire boat. I mentioned this to the mechanic, and he took it out for a test ride.

His diagnosis; the heat sensor could be faulty & sending an overheat message. He said he disconnected the sensor & the boat was a Mako shark again.

He also said he is not sure if the sensor is bad & that I should just watch the tell-tale flow to make sure the water flow is ok.

I am thinking I should replace the sensor & install a temp. gauge.

My questions please;

1) Would it make sense to replace the heat sensor?
2) Would it make sense to install a temp gauge?
3) If 2 above is "yes", is it even possible to install a gauge on my ancient '98 Evinrude?

Many thanks gentlemen & sailors.

 

[boobie]

Replace the heat sensor and the mechanic.

 

[Bosunsmate]

Haha id agree about replacing mechanic too, problem is you a quite likely to end up with a similar one.
I installed a gauge on mine but it becomes no more than a novelty after a while. I like having my eyes up and not in the cockpit so so long as you have a good heat sensor and a loud horn then id start and finish with that.

 

[boobie]

Good idea !! Let your ears do the motor work for you and keep your eyes on what's going on around you.

 

[Faztbullet]

You need to find a different mechanic....
1) Replaced the impeller......likely needed
2) Replaced the fried powerpack.........it it got this hot you have other problems!!!!
3) Cleaned the heads and replaced the piston o-rings (apparently the previous owner had used silicone inside the heads)...that silicon is from the factory and needs silicon when heads reinstalled
4) Re-did all six carbs with carb rebuild kits. because it was idling rough........was it idling rough before overheat?
It it got hot enough to melt a pack and melt the overheat sensors the pistons are likely scuffed...no where is mentioned a compression test as this is the FIRST test you do on a overheated engine.

 

[gam101]

Haha id agree about replacing mechanic too, problem is you a quite likely to end up with a similar one.
I installed a gauge on mine but it becomes no more than a novelty after a while. I like having my eyes up and not in the cockpit so so long as you have a good heat sensor and a loud horn then id start and finish with that.

Could you please recommend a gauge set I could buy (hopefully not too expensive) for my Evinrude OceanPro 175HP '98 ?

 

[gam101]

Replace the heat sensor and the mechanic.

Believe it or not, this is my 2nd mechanic. The first one would work & not test anything. He would not bother testing the boat in the water or with the outboard in a tub, before or after his diagnosis. So trust me when I say this mechanic is many times better. For starters, he had the outboard in his tub throughout the time he was working on it. Good + trustworthy mechanics are really hard to find.

 

[gam101]

You need to find a different mechanic....
1) Replaced the impeller......likely needed
2) Replaced the fried powerpack.........it it got this hot you have other problems!!!!
3) Cleaned the heads and replaced the piston o-rings (apparently the previous owner had used silicone inside the heads)...that silicon is from the factory and needs silicon when heads reinstalled
4) Re-did all six carbs with carb rebuild kits. because it was idling rough........was it idling rough before overheat?
It it got hot enough to melt a pack and melt the overheat sensors the pistons are likely scuffed...no where is mentioned a compression test as this is the FIRST test you do on a overheated engine.

Appreciate the detailed reply. I'm concerned now for the health of the pistons. :facepalm: I've never done a compression test before & quickly googled the link below. Am I on the right track?

I am certainly going to replace the heat sensor, after I determine its location. Intending on sharing the outboards pics here later, so you guys can point it out for me.

I am learning as I go along. Thank you all for the patience & the tremendous help.

 

[Bosunsmate]

Could you please recommend a gauge set I could buy (hopefully not too expensive) for my Evinrude OceanPro 175HP '98 ?

Its being more than yonks since i had one so i cant sorry, i think mine was just one that people install in their cars, it was quite cheap but worked.
One bit of info that may be useful to you is that i did buy a small tube of thermal grease which helps to get the heat transferring to the sender pickup unit from the engine efficently. Electric shops sell it cheap.

A compression test can also be got rather cheap, ive a $10 one you just hold on the end of the cylinder, i jack up a little starter button off the solenoid so you can do the test holding the compression tester if no one is around to turn the key in the boat

 

[Bosunsmate]

You said it was shaking and things but then later the mechanic took it out for a ride and it went like a mako shark which i assume means it went good.
Did you see this or have you taken it out to verify this for yourself?

 

[gam101]

You said it was shaking and things but then later the mechanic took it out for a ride and it went like a mako shark which i assume means it went good.
Did you see this or have you taken it out to verify this for yourself?

Appreciate the replies. Yep, Mako Shark = Good (following the heat sensor disconnect, the shake was gone & full throttle was no issue). And yes, I was on the boat with the mechanic for the test when he explained the possible faulty heat sensor.

Ok, so I guess my action items are;

1) Find a heat gauge online that I can purchase & install. (hopefully someone else here will direct me to one)
2) Replace the heat sensor & apply thermal paste to it while during installation.
3) Execute a compression test to check on the cylinders.

Anything I miss?

Thanks again.

 

[Bosunsmate]

That was the heat gauge i used the thermal paste with but id reckon id put some myself on a heat sensor if i did one of them too although best to check with the manufacturer as I find quite often even on something that seems so straight forward that for some wildly obscure reason things actually have to be done just one particular way. A email to them often gets a prompt reply from someone actually in the know there.
Nope, nothing missed, its a easy as 1,2,3

 

[Sea Rider]

An overheat sensor doing its homewrok right should make OB to run towards safe idle rpm or even stop engine not to overheat severely. A temp gauge by itself is only good to see how fast needle rises towards red zone and how your beloved OB is fried in front of your eyes...

Happy Boating

 

[Chris1956]

Gee, There is a real low-tech test for overheat. Run the motor and put your hand on the head with the two-wire temp sensor. If you can keep it thee a few seconds, the motor is not overheating, and the sensor is shorted to ground.

If she is overheating, the impeller, gaskets and perhaps the waterpump housing need to be replaced. Also check/replace the two thermostats, as well.

 

[Faztbullet]

There are 2 of them on engine....

 

[gam101]

Appreciate all the messages again. And the tremendous help. :joyous:

So, below is the OB from one side, and I am guessing red arrow marks the heat sensor. Am I correct in assuming that I have to open the head to unscrew it & install the new heat sensor? (this was suppose to easy like an O2 sensor on a car)

 

[gam101]

Gee, There is a real low-tech test for overheat. Run the motor and put your hand on the head with the two-wire temp sensor. If you can keep it thee a few seconds, the motor is not overheating, and the sensor is shorted to ground.

If she is overheating, the impeller, gaskets and perhaps the waterpump housing need to be replaced. Also check/replace the two thermostats, as well.

Appreciate the advice. Thermostats? Where would they be located? Somewhere near the impeller?

 

[Bosunsmate]

Thermostats are under the hex shaped housing above the spark plug. But i wouldnt go opening them up and risk damaging the o ring unless you know they are the problem. Feel both heads, are they a similar temperature, that will tell you if one thermostat has broken, to have two go down at the same time would not be very likely. I think you need to run it at idle on muffs or in a barrel and check temperature on both heads and then develop a plan.

Yes that middle thing is the overheat switch unit, ive never had to replace one so not sure how thats done but it definitely looks like you dont have to remove the head so keep your wrench in its holster for a while longer before embarking on that as someone else will know

 

[Chris1956]

Gee, that temp sensor should have a plastic hex head "nut" holding it to the block. Yours looks to be broken off. If you have a voltmeter (ohmmeter), test the tan/blue wires on each of the two sensors for continuity to ground, with the engine cool. If either is grounded, that sensor is bad.

The fact that your temp sensor "nut" looks to be broken off, is suspicious.

I would test/replace the thermostats, if the sensors test OK.

 

[Faztbullet]

Besides all the patched wiring with tape....if the motor go hot enough to melt pack it has melted the "salt shaker" t-stats in heads......