EVINRUDE 150 HP

[wargan]

Hi, I recently had my 150hp spitfire series Evinrude motor(1991) serviced. It is in excellent condition and has only done 200hours. <br /><br />Before the service the temperature gauge was halfway in the green while planing at 3-4000 revs. On idle it was 2/3rds into the green.<br /><br />After the service it was running 1/2 way into the green on idle but once I put it up to 3 or 4000 revs it dropped down out of the green.<br /><br />Took the boat back to the marine dealer and they did various checks. Thermostats OK. Temperature on idle, both banks, 60degrees. On 4000revs 40 degrees. They couldn't give me any answers but tried to assure me I wouldn't do any harm to the engine if it were running cold.<br /><br />Anyone know whether that is right?<br /><br />Secondly, what should be the operating temperature at speed? Is 40 degress too cold or not. If its OK then the gauge has become cactus for some reason.<br /><br />If the temperature is too cold, any ideas as to what the problem is and how I fix it.<br /><br />

 

[Joe Reeves]

Re: EVINRUDE 150 HP

Tarka.... THere were two different 150hp models manufactured in 1991 and I have no idea which one the Spitfire is (would need model #), however the thermostat areas are identical.<br /><br />The thermostats open at approximately 143° which is required. Their purpose is to heat the water at the aluminum casting area which surrounds the steel cylinder wall outside of the cylinder to compensate for the distortion that takes place within the cylinder when the engine is running.<br /><br />If that temperture is not reached for any reason, and the engine is allowed to run cold, there is no compensation for the distortion. This results in scored pistons and cylinder walls! You state your engine is running at 40°.... is that a typo? Does the cylinder heads feel that cold?<br /><br />At the top of each cylinder head, there is a plate attached to the head with four bolts. In back of that plate are the thermostats and also the water bypass valves.<br /><br />I would assume by what you've said that:<br />Either you have faulty thermostats, no thermostats, the bypass valves are missing, or the bypass valve pressure springs are missing. Strange that this cold running problem did not exist before having the engine taken to the shop.<br /><br />If you do not have a parts or service manual that shows the exploded view of the thermostat area, reply to me at my e-mail address with a request for that detail and I'll send it to you so that you have an understanding of what I'm speaking of.<br /><br />ReevesJ32@aol.com

 

[Brew]

Re: EVINRUDE 150 HP

Just a thought on the temperature readings....are we confusing celsius and farenheit? 40 celsius would be about 104 farenheit. Still too cool based on the required 143, but makes a litte more sense.<br /><br />Brew