1971 EVINRUDE 50HP HYRO-SHIFT OVERHEATING

[rickr]

I’ve never posted here but have learned a great deal about outboards from other posts. I did a search for my problem but did find the answer need. So everyone's help is needed. <br /><br />Recently my 1971-50hp Evinrude hydro-shift started overheating, at least that’s what I believe the buzzer signifying. I replaced the water pump a few months back, took the boat out for a few hours with no problems. Last week I took the boat out to do some fishing ,after the boat sat for 2 months, the **** buzzer starts going off. I shut the motor off then after it cooled down (believing it was overheating) I re-started the motor, shortly after that the buzzer sounded again. So I replaced the thermostat. Before installing the new thermostat in I starter the motor to see if water was making it to the top of the motor, which it was. I thought things were fixed but yesterday I found out there not. What’s next?

 

[The Marine Doctor]

Re: 1971 EVINRUDE 50HP HYRO-SHIFT OVERHEATING

Check the compression for a blown head gasket.<br /><br />TMD

 

[rickr]

Re: 1971 EVINRUDE 50HP HYRO-SHIFT OVERHEATING

okay here's what I checked today.<br />compression 150 on both cylinders<br />water pump working fine no damage<br /><br />what's next?

 

[OBJ]

Re: 1971 EVINRUDE 50HP HYRO-SHIFT OVERHEATING

Rick....first you need to verify if the engine is really overheating. When the alarm goes off, this will be a steady tone, pull the lid and see if the block is really overheated. This will be readily apparent as you will not be able to touch any part of the block with out getting burnt real quick.<br /><br />If it is overheating, you may need to pull the lower unit and check the pump again. One place that can cause problems is where the water tube enters the pump housing. Sometimes the tube can catch the lip of the rubber grommet it slides into and bends it over restricting water flow to the head.<br /><br />If you think the engine is ok, look at the warning horm in the controls and make sure there is no electrical shorts causing the horn to go off.<br /><br />Not often, but the heat sensor in the head can go bad. These have bi-metal parts in them that make them work. I've seen them go bad on occasion and bring in the overheat alarm to soon.<br /><br />Do keep up posted...Thanks.