1987 Evinrude 40 HP 2 cycle overheating

Rapid Robert

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Jan 13, 2009
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~~Tell tale it putting out a good stream. After idling with the muffs on for about 3 minutes the stream becomes very hot and alarm comes on. This also happened last week when I had it in the water.
At first I thought the VRO was not working because I was not getting very much blue smoke from the exhaust. The oil line from the reservoir to the connect fitting on the motor is clear...I pumped the bulb and oil flowed freely. Not sure if oil is being mixed to the power head. I have to check the VRO pump next, but before I do...can the tell tale stream be strong and the water pump still be bad? Thanks for your help
 

Bosunsmate

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Apr 7, 2012
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yes but it can also be your thermostat..
lots of people remove those vros and premix
you may need to do a compression test if you think its being running without oil
 

Rapid Robert

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Jan 13, 2009
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Thanks Bosunsmate for your reply. I can't find anything in the manual regarding a thermostat. Do some models not have one?
 

Rapid Robert

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Jan 13, 2009
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I am waiting for new thermostat (I finally found it after removing head).

I did a compression check and each cylinder read 150. That seems too good to be true. Is it?
 

bonz_d

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Apr 22, 2008
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That compression sounds pretty normal for those 2 cylinder engines. I have 3 different ones and all have compression in the 140 to 150 range.
Best to also run that with some premix until you get the VRO pump verified. Check all the hoses and fittings from the tank to the pump. Even a small air leak will cause problems.
 

Fleetwin

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Nov 23, 2011
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Verifying oil pump function is easy.

1. Pre mix some fuel.
2. Draw a line on the oil tank with a marker at the current oil level.
3. Go run the engine.
4. Can you see a drop in oil level?

I would bet you have a thermostat issue. My 2-cyl. 50 did that and the symptoms were identical to yours.
 

jakedaawg

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Jun 26, 2012
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I hope you are not squeezing the bulb on the oil line. That bulb is only used to prime the system initially by the VRO pump installer. If you did squeeze that bulb, and were able to squeeze it, you have an issue.
 

Rapid Robert

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Jan 13, 2009
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I did buy a new thermostat because the old one was stuck, partially closed. I am now putting the head back on, after getting a new gasket. My question is: How important is it to use a torque wrench when tightening the head bolts? I have tightened the bolts by alternating back & forth and up & down to tighten evenly all the way around. I have tightened the bolts as tight as I can with a regular wrench. If I should have used a torque wrench, is it too late to go back and loosen the bolts and start over with a torque wrench?
 
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