Evinrude overheats

[Droll]

Got some problems whith my old Evinrude 50 hp 1971 #50173 .<br />Have done :<br />#1 New impaller<br />#2 New thermostate<br />#3 Got new pressure release valve ( old was missing )<br />The engine is running until the alarm start, then I stop it.<br />Waterpump are working ,but are not shure if it can produse enough pressure .<br />Did connect my drill on the shaft , got the water 12" up in the air ( drill rpm 1000 +/- ) <br />Have tried to connect waterhose on the water tube (removed lowerunit and lowered the remaning part in to water ), The engine did not overheat .<br />Have removed every cover where it is supposed to be water channels .<br />Have used the waterhose to flush bouth ways .<br />I am using 2/3 of an old oil barrel to lower the engine in to .<br />What to do next ?,borrow a 12 gage and send the Evinrude to the next world

 

[oldboat1]

Re: Evinrude overheats

Delay the execution. The impeller might be spinning on the shaft -- shaft key not engaged. It sounds like you have touched on likely causes, so think of something simple that might have been overlooked. Air leakage around the impeller housing might also be the culprit.

 

[Droll]

Re: Evinrude overheats

Did use some god sealer on the pumphousing so I don´t think there is any air leakage , did also use sealer under the wearplate .<br /><br />

The impeller might be spinning on the shaft -- shaft key not engaged

How can this happend when <br />

Did connect my drill on the shaft , got the water 12" up in the air ( drill rpm 1000 +/- ) <br />

But I got one question , what is the lenght on the water tube ? , on my engine it is 15 - 20 mm longer than the " driveshaft tube " , can the tube be bendt or .....<br />How tight must the pumphouse be around the driveshaft ? I have added a seal ontop of the house , did take a look on some other engines and they al had seals ( was nothing on my 50 hp lost by last owner ?)

 

[oldboat1]

Re: Evinrude overheats

Hi Droll,<br /><br />As I picture it, you are putting the detached lower unit in water, then pumping water by using a drill to turn the driveshaft. If that is working, then it does sound like the impeller is properly installed. I usually just turn the shaft clockwise by hand before reinstalling the lower unit -- can feel the resistance of the impeller if it is turning with the shaft.<br /><br />It sounds like you have also forced water up through the water jackets (lower unit detached) through the water tube. I also do that to insure the passages are clear. I think you would need to remove the thermostat to force water through in this manner.<br /><br />You can see if the engine is indeed overheating by carefully placing your hand on the top of the cylinders when the engine is running. If you can hold your hand there for at least a few seconds, the engine is not running hot (probably 130 degrees F or less). If the engine is not running hot, the overheating warning system is obviously suspect -- don't know how the system is set up on your model, but the sensor is probably in the vicinity of the area you are testing for temperature on the top of the cylinders. The sensor could simply be bad.

 

[Droll]

Re: Evinrude overheats

Your picture looks just fine .<br />But the powerhead are to hot .<br />I am thinking about 2 or 3 problems :<br />1. The pump can´t give the pressure .<br />2. The pressure release valve is to tight/hard ,not enough pressure to open it<br />3. The water tube is to short/bendt,and give me a water leak I can´t see .<br /><br />When I used the water hose ,pressure was no problem and the puwerhead was cold ,maybe to cold.<br /><br />The sensor is placed in front on the top of the cylinder head , if the pressure valve don´t open .....<br />I will try to remove the valve ...se whats happening .

 

[oldboat1]

Re: Evinrude overheats

would try running without the thermostat and see if the overheating is still a problem. Other than that, running out of ideas.... If water circulated properly when forced in, it's not a problem with the physical connection of the tube at the powerhead -- but it could be that the tube is not seated/reinserted properly at the water pump when you reinstall the lower unit to test engine operation(?) I'm guessing that the tube slides into the top of the waterpump housing to a depth of maybe an inch?

 

[Droll]

Re: Evinrude overheats

Todays update <br />#1 Straighten the water tube , 2 - 3 mm in lenght.<br />#2 Did apply "heavy" load of sealer OUTSIDE water tube , 10 mm from bottom and up to 30 mm from bottom.<br />#3Did remove thermostate and pressure valve .<br /><br />And then run the engine for 10 - 15 min . high idle ( 1000 rpm +/- ).<br />Temp of exhaust cover 20c > 25c<br />Temp cylinder head 20c > 25c.<br />The engine is running cold....<br /><br />And the problem ?<br />Defect/wrong thermostat ?<br />or to hard spring on the valve ?. <br /><br />Thanks for the support .