Hot alarm goes off

[sam11400]

I have a johnson 150 outboard. Every time I pass 3000 rpm my hot alarm goes off. I changed the water pump and the thermostats. What could be wrong? Can I drive without the thermostats? I have a great stream out of the pee hole. Please help.

 

[Watermann]

What year of motor is it? Was the impeller you removed damaged and missing any vanes?

 

[Faztbullet]

On a Junkrude pee stream just tells you impeller is working and nothing about cooling. Need year and noyou cannot run it without t-stats,

 

[Scott Danforth]

welcome aboard.

where are you located? where are you boating? fresh water, salt water?

if your block passages are plugged, you will still get a good tell tale stream, however no cooling.

let us know what motor you have and where you are located. And if you are boating in Florida, and boat in salt water, yes, your block passages are most likely plugged and can only be mechanically cleaned (by pulling the block covers off and poking the crud out)

 

[Willyclay]

BTDT with an old V-4. My problem went away when I replaced the temperature sensor in the cylinder head. Your V-6 may have more than one sensor. Good luck!

 

[Klink]

welcome aboard.

where are you located? where are you boating? fresh water, salt water?

if your block passages are plugged, you will still get a good tell tale stream, however no cooling.

let us know what motor you have and where you are located. And if you are boating in Florida, and boat in salt water, yes, your block passages are most likely plugged and can only be mechanically cleaned (by pulling the block covers off and poking the crud out)

Exactly right.

I'd test the engine head temperatures with an infrared thermometer gun, an excellent tool to have, and only like $17 on Amazon. I got this one: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 .

I've bought 3 1990's Johnson engines (in Florida) and all three peed fine but still didn't get any water to the heads because the water passages were clogged. An engine turning off like yours in my recent experiences is actually good, because it saved the engine from frying.

Read the instructions that come with the thermometer. Although the thermometer's pointing infrared red dot stays the same size always, the place that it takes reading gets wider the further out shoot from. If you want to read exactly where the red dot points you'll have to be like 6 inches away. It's a great tool to pinpoint the hot spots. After I completely cleaned out all the water passages on my 115hp, I placed a temperature gage probe on my 115hp where it was the hottest, so that I could be from the hottest spot, and the gage on the panel told me the temperature. Moreover, I installed a water pressure gage to the water pump. I am now warned of any changes. I once had some debris block the inlet a tad and found it out because I saw the temperature go up from the normal temperature to just like 15 degees higher, but still way below any over heating. That's what I put in the temperature gage for.