1984 Johnson 115 Temp alarm

I have a 84 Johnson 115, I have replaced the water pump but I'm still getting a temp alarm. Does anyone have any sugestions to try next.

Check your thermostats.

Ok thanks. Do you have to pull the powerhead to check?

No...........

Thanks for all of your help, but one more question. How do I check them? Thanks again

Thermostats are put in boiling water to test them.-----------------------But have you checked the water deflecters ?----They can be inspected by removing the cylinder heads.----Do you have water flow out the tell tale ?

(Water Deflectors)
(J. Reeves)

Water deflectors are actually lengths of 3/8" outside diameter rubber hose, installed between the top cylinder and any cylinder beneath it, and also between the bottom cylinder and the block. The purpose of the deflectors is to have the water follow a definite path around the cylinder walls. Unfortunately the deflectors between the cylinders will at times swell sideways due to either a previous bad overheating problem, or simply due to age and salt corrosion. This causes a water flow restriction which usually allows the water to cool sufficently at low rpms but not at the higher rpms.

This hose material can be purchased reasonably at any automotive parts type store if you care to make your own, or you can purchase individual deflectors at any Evinrude/Johnson dealership at a somewhat higher cost.


Removing and installing them can be a hassle at times, but not always. I use a sharply pointed scribe with about 1/4" of the tip bent at a right angle whereas I can reach in, jab the tip sideways into the rubber, then yank it out. It's necessary to clean the seating surfaces where the ruber contacts the block with a small rat tail file to eliminate salt deposits etc. When installing the new rubber deflector, coat the deflector and the metal surfaces with WD40 which will act as lubrication to allow it to go in as easily as possible.


Make sure that you insert something into that deflector area before cutting and installing the deflectors if you make your own so that you will be certain that they are the right length and also that they will be seated properly. Usually a very small amount will be left extending about the block sealing area..... simply cut the excess off with a single edge razor blade.

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Stratos, you have a PM.

Yes it has water coming out the pee hole. I replaced the water impeller also.

Check insulation of tan wires from the sensors that they haven't cracked and are grounding out on the engine block somewhere.

Thanks

So,. have you found anything?

Water flowing out of the tell tale does NOT guarantee that water is circulating properly through the engine block.

Just a bit to think about....
When you get an overheat alarm, the very first thing to verify is "Is it actually overheating". Is it really too hot, or is it a false alarm.

That is the first. So, get a digital temp gun...like the ones they were using to check passengers for Ebola!!!....and measure the temp of the head
right near the temp sensor. Or, touch the head...you should be able to hold your hand on the head for a count of 3 or 4....before it become too uncomfortable. In fact, measure the temps all around the head....spark plug holes...thermostat housing....
The heads should run from 135 to maybe 150....thermostats are 142 degrees usually.

But find out if it is actually hot or not first. Don't just rip the engine apart....water deflectors, etc....it could easily be an electrical fault, or just a bad sensor.

daselbee said:

So, get a digital temp gun....

Click to expand...

I got this one, $17 delivered to you. http://www.amazon.com/gp/product/B00837ZGRY/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1 It works great. Read the instructions, to get pinpoint accuracy you need to place the infrared dot as close as you can to the spots. This way you can pinpoint all the hot spots. In my Florida experience (salt water, year round use, bad maintenance by Floridians?) 6 out of my 8 used engines I bought in the last year+ had totally clogged water passages in the cylinder heads. It's easier to test with the gun before taking everything apart. If you have a schematic of the cooling water route you can check them along the path with the gun.

Thanks for all the help from everyone. Have not found anything yet. I bought the block last year,the guy I got it off of said he had put it in a bath maybe that stopped up the deflector hoses. I will have to wait till we get out of this weather we are having.