186xt with 115 Etec-HO overheat alarm issue

[Bronzebackpro7]

Does anyone else with this setup have an issue with the overheat alarm? It seems to happen more when I am going at a quick no wake zone pace or slightly above. I have never had it happen when I am running flat out which makes me think there is something more to this? I don't believe the outboard has a low water pickup/intake and maybe this is causing it? Gets frustrating when I have to be dead in the water until the alarm times out and I can start it back up and go. Any help is appreciated

[Nightmare]

Do you have a water pressure gauge? Those numbers can be telling but if not... it's very possible that your water pump needs changed out. It can happen that the pump's weakness can generate enough flow at high rpms to keep the motor within temp tolerances but, is unable to maintain adequate flow at low rpms.

If this is your case, you can shorten your cool-down period by running the motor at lower-midrange rpms (2000-2500) while in neutral so you are circulating water thru the motor rather than doing an extended heat dissipation by air (remember: the motor is water-cooled and not designed to disperse heat to surrounding air). This is a stop-gap technique and NOT to avoid a proper fix. It is also a crapshoot without a water pressure gauge to show whether you are actually making ANY pressure to work with.

A low water pick-up has no benefit at low speed.

Have you noted the flow at the pisser stream? While not a very good indicator - if there is little/no flow, then the pump needs attention. If you boat in shallow sandy/silty waters then its also possible the system needs flushed.

Imo, the addition of a water pressure gauge (if you don't have one) helps to keep an eye on such issues in the future.

Really ought to take this to the Evinrude/Johnson forum for best possible results http://www.bbcboards.net/forumdisplay.php?f=4 .

[Bronzebackpro7]

Thanks. THe flow out of the outboard seems to be decent as its peeing pretty solid (pees straight out the back of Evinrude so you have to look around to even see it- pet peeve). No water pressure gauge on this model so thats why I am almost flying blind but makes sense with the water pump honestly. I'll probably go this route first

[JR19]

A water pressure gauge would be valuable. A smart gauge that hooks to the boats computer and gives engine temperature read out in real time would also be a great asset.

When/if the water pump was changed make sure everything was changed. Some people only change the impeller but it's best to get the kit that includes a new housing and other various parts and change everything. The price difference between just the impeller verses the kit is not that many $ so go ahead and have everything changed buy using the kit.

Healthy thermostats?

Anything mounted on the transom or jack-plate that night disrupt water flow to the intake passages?

[Nightmare]

Anything mounted on the transom or jack-plate that night disrupt water flow to the intake passages?

I would think that would be more likely during hi-speed operation but wouldn't discount it either.

[JR19]

I would think that would be more likely during hi-speed operation but wouldn't discount it either.

What you said is true but there is a small possibility at slow speed with the transom deep it might disrupt water flow differently than when on the pad with the transom higher in the water. This would be something easy to check so I threw that suggestions out there.

[Bronzebackpro7]

A water pressure gauge would be valuable. A smart gauge that hooks to the boats computer and gives engine temperature read out in real time would also be a great asset.

When/if the water pump was changed make sure everything was changed. Some people only change the impeller but it's best to get the kit that includes a new housing and other various parts and change everything. The price difference between just the impeller verses the kit is not that many $ so go ahead and have everything changed buy using the kit.

Healthy thermostats?

Anything mounted on the transom or jack-plate that night disrupt water flow to the intake passages?

Nothing mounted on the transom(ducer is shoot thru) and no jack-plate. I ended up getting the water pump and impeller kit along with a couple other general maintenance items so I am hoping that is it. I had contemplated getting a new thermostat as well but its too odd to me that it would only do it in that one range and not when running flat out.

[JR19]

Keep us posted on your results...FYI I have never changed the impeller on a 115 E-TECH but I have done it on my 150 HO. I don't recall the exact specifics but there will come a point in the process when you have to twist and pull on the drive shaft until it pops so parts disassemble/reassemble correctly. I never had to do this helping my friend with his Mercury and I don't know if its just an E-TECH thing or or possibly just a 150 HO thing. If my memory is correct the directions in the water pump kit explain how to do it. I also found a youtube video that shows how/when/why to pop the driveshaft.