65hp Evinrude cooling Question

[piggy]

Got a 1973 65hp Evinrude remote long shaft. Pumps water fine. Checked by taking cover off thermostat and running motor in tank shot water out poppet value 4ft. Replaced cover but don't see warm water coming out anywhere. Should water exit out rear of motor in middle two holes at rear. Run motor in water at fast idle for 20 minutes used heat gun to check temp never got over 140 F. Where does water exit? What am I missing? Does thermostat only open at higher speeds when motor runs hotter? Thanks

 

[tashasdaddy]

Re: 65hp Evinrude cooling Question

mist out the exhaust relief ports at idle, faster rpms, it goes out thru the prop with most of the exhaust.

 

[jay_merrill]

Re: 65hp Evinrude cooling Question

The primary exit point for cooling water on your engine is in the gearcase, just above the cavitation plate. Look for verticle slits on either side of the case, directly above the prop shaft. If you run the motor on muffs, you will see water exit at this point, as soon as the t-stat opens. The holes in the back of the midsection are relief exhaust points. You may see a small trickle of water out of them, but most often all you get, is a bit of spray.

The t-stat opens according to water temperature and the motor does not have to be running at high rpm for this to happen. In fact, it should open with the engine at idle, in most cases.

What opens at high rpm, are a pair of pressure relief valves, located in the cylinder head cover, in the vicinity of the t-stat. These are essentially poppet valves and they will open, once engine rpm (and hence, water pump rpm) reaches a point, that creates a certain water pressure in the cooling system.

Try putting your motor on the muffs. Don't turn the water pressure from the hose up high enough to force feed your cooling system - just feed the pump and let it do the work. About 60 seconds or so after you start the engine, you should see a good flow of water coming out of the verticle slits in the gearcase.

 

[piggy]

Re: 65hp Evinrude cooling Question

Thanks for the help. One more question does this motor have a warning buzzer or shutdown for over heating? On the right side of the top cly. there is what appears to be a temp sensor if it is how does this work, if not what is it. Can't find any referance in the manual. Thanks again

 

[jay_merrill]

Re: 65hp Evinrude cooling Question

There are two sensors - one is the one on the top right (starboard) side of the head and the other is on the lower left (port). There is an overheat warning horn inside of your control box. You should test it in accordance with the instructions in your service manual. If you don't have a factory issued manual, you should get one. They are available in a variety of place, including online.

The other sensor is for the automatic choke feature on your engine. It is recomended that it be disconnected (Service Bulletin 1335), because it has a tendancy to make the motor run rich at times. If you disconnect it, don't forget to jump the two terminals specified in the instructions - if you don't you will only get half actuation of the electric choke, when you use the choke switch at the control box.