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1982 Evinrude 140 overheating

S

Scod

Member
Hi guys, my Evinrude 140 is overheating. It was running fine then I lost a cylinder. It turned out to be a faulty trigger which I have replaced. Since then it idles and runs well and if I keep the RPM low it's quite happy but when I open the throttle I get the overheating alarm after about 15 seconds.

I have replaced the impeller and also put a new thermostat kit in. It pumps water out the telltale hose and water comes out the propeller and the two little holes next to the gearbox.

Any help is appreciated. Thanks
 
Water out the tell tale does not mean that water is moving through the block properly.-----------Perhaps the diverters in the block are not allowing proper flow.---------
 
Scod said:
I removed the hoses to the thermostats and have good water flow out of the heads so it's good up to that point. Here's a video of it idling. Seems to me like a good amount of water coming out at the prop.

https://youtu.be/zntixXOAOyI
Click to expand...
Unfortunately using muffs and a hose are not going to give you a true indication of how well water is flowing in this engine. You really need to run it a barrel or the lake so that the water pump is doing the work. If you can get an IR temp gun you can measure temperatures on each as the engine runs.

KJ
 
Are the exhaust waters hotter than normal, You should be able to hold hand in telltale stream indefinitely, Should be able to hold hand on head surface for a 6 second count without scolding fingers if she's running a normal temperature 160 being the high limit, thermostats start opening around 143 degrees
 
Took it out today. As expected after about 20 seconds of open throttle it overheated and the buzzer went off. The port side head was far hotter to touch, and to confirm that side was the issue I disconnected the temp sensor wires one at a time. I then removed the hose from the thermostat and cable tied a piece of garden hose into it to extend it outside the motor cowl. I took it for another blast and it was fine, gave it a good 5 minutes of full throttle without overheating.

I removed the thermostats and put them in a pot on the stove to see how much difference there was and the bad one opened a little after the good one. Will get a thermometer to see exactly what temp it opens at.

Annoyingly this is a new thermostat that I recently installed so I know exactly what's involved to reinstall it. I've now drilled holes in the cowl to give me access to the bolts and something to to press on to compress the springs. What's the best trick to make this easier?
 
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