When I bench test a horn it only works one way. Must be a diod. Wire from the sensor is the ground.
The horn part that I listed is the correct horn for your motor.
Don't run that motor anymore except for short times trying to see if it is going "into" an overheat. Find out whether you have tool issues or overheat. I have a cheap Harbor Freight IR gun and it works fine.
Run motor in driveway only. Diagnose, repair then use.
Now you need to know why your alarm isn't going off. That sequel you hear that I can't could be a failing horn.
Ground the tan wire with the key switch on....no sound, open up control box and hot wire horn and see if it's dead.
When I test for overheat at the first sign of going over...
Nope, he later disclosed that he had removed the bolts but two of them broke off. Salt corroded broken bolts would have given us a clue that the driveshaft wasn't frozen in the powerhead.
Alls good with the OP so their really is no more reason to post here.
Well if your having trouble getting the bolts out then I'd pickel it in vinegar and see what happens.
When I'm working on salted out small outboards, I pull the gearcase, turn the motor upside down, pour salt away down the water pump tube and let it fill the powerhead.
Not perfect but helps...
I use salt away.... saltchuckmatt.
For a less expensive way....get a plastic barrel and put a couple of jugs of vinegar mixed with water. Run it at idle (if it will without overheating) for 1/2 hour or so and shut it off.
Let it sit for a week then test again.
Didn't you already pull your...
You will want to flatten that head now that it's off. Dead flat surface, 120 sand paper laying on the flat surface and do figure 8 patterns on it until it's shinny everywhere.
Once you get it running you need to check head temp even if it's pumping water correctly. IR gun or check with your...
This company claims too....also, omc must have made them...pretty common motor.
Click on Evinrude Johnson, download, find your year and it shows the price
https://www.outboardjets.com/jet-drives/
