74 Evinrude 135 v4 overheating

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marksams

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Aug 3, 2003
Messages
3
My 74 Evinrude v4 135 HP starting overheating all the sudden. I have replaced the impeller, checked vernatherm and have water coming out of motor when running. I can see when the vernatherm opens. Cylenders 2 & 4 seem to be running normal temp (can touch while running)while 1 & 3 are running hot(cannot touch while running). Temp guage goes into the red. Temp sender is on cyl 3. I removed hoses on back of motor. A stream of water is coming through the heads on 2 & 4. Just a small stream of water on cyl. 1 & 3. Does anyone know why I am not getting water through half the motor?
 
W

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 74 Evinrude 135 v4 overheating

Sounds like a probable internal blockage. Was any part of the old impeller missing? If so, it may be lodged in the coolant passageways. A shop manual will be helpful, since they have good cooling system diagrams. You may be able to clean out the cooling system by removing the vernitherms and using compressed air or a water hose to flush.<br />Good luck!
 
M

marksams

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Aug 3, 2003
Messages
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Re: 74 Evinrude 135 v4 overheating

The old impeller was still intact and looked good. I removed the vernatherm and blew air and water through the engine from every hole I could find, including having the lower unit removed. Everything seems clear.
 
D

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: 74 Evinrude 135 v4 overheating

How did the head gaskets and deflectors look? If they were changed and it's still doing it I would consider pulling the cover off the heads (yes, both) and clean out the passages in the heads.<br /><br />Good luck!
 
M

marksams

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Aug 3, 2003
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Re: 74 Evinrude 135 v4 overheating

I took the head off and found that there was a blown head gasket. The gasket was allowing water to enter the cylinder. Thanks for the help.
 
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