'91 115 Evinrude, new impeller, telltale working O-Temp warning

[hunt-fish.com]

I just changed the impeller out. All back together running fine on the muffs. After a few minutes the over-temp warning horn goes off. The stream is strong out of the telltale and the water is warm not hot. Any ideas/help greatly appreciated. My other 115 Johnson runs for a long time and I never get an o-temp warning on the muffs.

Thanks,
John

 

[Silvertip]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Did it do this before you changed the pump? If not, you didn't get the water tube lined up properly, the impeller vanes are pointing the wrong way, thermostat is stuck shut, to name a few.

 

[hunt-fish.com]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Yes it did sound the O-temp horn before. Much quicker though. There is stronger flow through the telltale now. At least it seems like it is stronger. The lower unit is not leaking water all over the place now like it use too. I think the water intake grommet was missing in the old housing causing the water to leak out through the seams and everywhere else.

One thing I noticed before was when on the lake crusing no o-temp horn. Slow down and let it idle a while and the o-temp horn would come on. I would speed up and it would go off. I can watch the water pressure gage on the dash. I'm getting 5 PSI at idle. It's idling at around 850 to 1000 rpm's. No leaks in the water lines to the gage or under the cowling..

I bought a thermostat kit and that was my next adventure. Is that the next step or something better first?

Is this just typical with a big motor on the muffs? I have the dual input muffs designed for the big motor.

BTW - this motor has been in saltwater by the previous owner. Don't know how well he took care of it.


Thanks,
John

 

[limacina]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Saltwater issues can usually be like heart attacks. Your atteries are clogged and fine at idle but if you go for a jog and the flow can't get through, Bang!
Not always though

 

[OBJ]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Check the heads when the alarm comes on. Each head has it's own t-stat and one can overheat while the other runs at normal temp. Might be a good idea just to replace both t-stats anyways.

If changing out the t-stats don't work, run some Salt-Away through the engine. Might clean it out.

 

[hunt-fish.com]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

I was leaning toward the T-stats since I don't know their condition. Not sure how hot the heads should get? I think the t-stats are 140 degrees F, not sure, I'll have to check the manual. I've toy'd with the idea of taking them completely out since the water is pretty warm here.

Any tricks to change the t-stats? I bought a t-stat kit when I bought the impeller kit. I think I have to split the lower housing to get to them?

Also, the engine hasn't been in salt water for 5 years or so. The water in the lake I take it to is somewhat Briney though. Don't know if salt away will help at this point?

Thanks,
John

 

[OBJ]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Temp is easy to check. Let the engine idle until warm. Then, lay your fingers on the flat areas just on top and in front of the heads. Should be able to leave them there for several seconds before having to remove them. If either is hot, you will know it.

I believe the stats are 143* stats. And on bubble backs, they can be a pain in the butt to change out. If the bolts (3) are stuck or corroded in, this makes it worse. Splitting the lower cover under the engine pan will help. I often think it's just as easy to pull the power head and get the job done than messing with the lower shroud and making up new descriptive adjectives to vent your feelings.

EDIT: Just one more thing.....the starboard head usually runs a little cooler than the port head.

 

[emdsapmgr]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Suggest you take the thermostat housing apart. The valve body has two extremely small holes which get plugged up with use. If these plug up, the engine will overheat at idle. They permit hot water to get to the back of the thermostat, enabling it to open at idle. Once you are moving the pressure relief valves open, providing cooling at higher speeds. When you are in there, replace the stats and check the relief valves to be sure they are not warped from heat.

 

[hunt-fish.com]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Thanks Guys! I'm going to read the manual this AM and dive in. Seloc manual looks like it doesn't cover thermostats but, the OMC manual does. They look like they will be tricky to get off. Hope it's not going to be an all day event. It's going to be 102 degrees today.

On these small holes will I need to run a small wire through the holes?

The kit I have has everything including new pressure relief vavles. I'm going to replace everything.


John

 

[hunt-fish.com]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Well, I decided to wait until I got an infrared heat gun. After running for a couple of minutes the temp on the starboard side ramps up to 200+ degrees before I shut her down. Port side getting up to 165 but, no warning sense. I also verified that the starboard sensor is indeed what is causing the alarm. However, the sensor isn't going off until around 200 degrees. The stats have got to go. Question: If I replace the stats and clear the small holes and it still gets hot, what's next? The deflectors? Get a new motor? I'm afraid the saltwater cancer may be getting malignent.

My identical 1990 Johnson 115 stays around 142 degrees at idle with same test conditions on both sides.

Thanks,
John

 

[91cajun]

Re: '91 115 Evinrude, new impeller, telltale working O-Temp warning

Well, I decided to wait until I got an infrared heat gun. After running for a couple of minutes the temp on the starboard side ramps up to 200+ degrees before I shut her down. Port side getting up to 165 but, no warning sense. I also verified that the starboard sensor is indeed what is causing the alarm. However, the sensor isn't going off until around 200 degrees. The stats have got to go. Question: If I replace the stats and clear the small holes and it still gets hot, what's next? The deflectors? Get a new motor? I'm afraid the saltwater cancer may be getting malignent.

My identical 1990 Johnson 115 stays around 142 degrees at idle with same test conditions on both sides.

Thanks,
John

^^^