I seem to have an overheating problem. 1977 Evinrude 55hp. The boos says that at low rpm/idle the temp should stabilize above 125 degrees and less than 165 degrees. At higher than 4000 rpm the temperature should be less than 125 degrees due to much more water movement. With my motor in the water idling it climbs above 165 degrees. I have an IR temperature gun and the head temp kept climbing up to 211 degrees before I stopped at slow speed. I run it at medium speed and the temperature starts down immediately and stays around 150 degrees. I couldn't check at higher speed because it was too late in the evening and it was quiet time on the lake. I suspect the impeller needs replacing and would like to do it myself it is not too difficult. I have the service manual for this motor but it is not real clear just what has to be taken apart to get to the impeller. I suspect I have to drop the lower unit but am not sure what that involves. Is this something a DIY guy can do? If so just what holds the lower unit to the upper? The manual has a step by step instructions fro REMOVAL OF GEARCASE. Is this the same as the LOWER UNIT? It requires removing the starter to get to the shift rod to lever bolt and remove this. Then remove the trim tab and 5 bolts (one countersunk). Is this the complete and correct procedure to drop the lower unit and get to the water pump and impeller? Does the lower unit just slip down off the upper once these bolts are removed? I assume I take off the prop so that it is not in the way. Then it looks like the water pump easily comes up off the lower unit to expose the impeller inside and under the pump. Correct? Is it difficult to get the shifter shaft back up and into correct position on reassembly?
Thanks a lot for your advice on this.
RubyCreekTed
OK, I gave up waiting for answers to my first post and after more reading I jumped in with both feet. I had no problem getting the lower unit off. I took the water pump off and as I suspected the impeller was smoked. The water pump is also very overheated and a lot of impeller material is fused to the sides of the pump and in the output port. I will try to clean it up. Can anyone tell me what is included in a water pump rebuild kit? I will post this question separately too.
RubyCreekTed
1977 - 55hp Evinrude How to repolace impeller
Linear Mode
