My engine continues to run hot

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WalterJS

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I have a 1978 20' Wellcraft with a 1983 150hp Evinrude, which continues to run hot even though I just had the water pump replaced and the thermostats removed. Also, I can only get the boat up to 3500 RPMs and... once it starts getting warm I have a loss of power and am only able to get it above 2500 RPMs. The propeller is approximately 14 inches in diameter. Any help would be appreciated.
 
tashasdaddy

tashasdaddy

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Re: My engine continues to run hot

your rpms drop because you are running hot.
i suggest that you check compression, blown head gasket can disrupt water flow. also check the diverters in the cooling system. get the tstats back in it after you find the problem.
 
kenmyfam

kenmyfam

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Re: My engine continues to run hot

Restriction in water flow somewhere by the sounds of it. How is the tell tale ?? and are you getting any flow out of the relief ports ?? if so at what speeds and how is the temperature of the water coming out. Have you checked the head temperatures ??
 
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WalterJS

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Re: My engine continues to run hot

tashasdaddy said:
your rpms drop because you are running hot.
i suggest that you check compression, blown head gasket can disrupt water flow. also check the diverters in the cooling system. get the tstats back in it after you find the problem.
Click to expand...

I was told the copression is a little low but not bad for an older engine. Nothing to indicate a blown head gasket.:confused:
 
kenmyfam

kenmyfam

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Re: My engine continues to run hot

WalterJS said:
I was told the copression is a little low but not bad for an older engine. Nothing to indicate a blown head gasket.:confused:
Click to expand...

You really need to define "a little low" Can you post the compression on each cylinder ??
 
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WalterJS

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Re: My engine continues to run hot

kenmyfam said:
Restriction in water flow somewhere by the sounds of it. How is the tell tale ?? and are you getting any flow out of the relief ports ?? if so at what speeds and how is the temperature of the water coming out. Have you checked the head temperatures ??
Click to expand...

Only got the boat three weeks ago and I'm learning my way around. I am adequete with car engines or motorcycle engines. I am floundering around a bit.
How would I check these temperatures?
 
aclmvh

aclmvh

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Re: My engine continues to run hot

Go to Harbor Freight or some such and get yourself a digital laser thermometer0 $8 at Harbor Freight. Your heads should not get above 150 degrees.
 
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WalterJS

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Re: My engine continues to run hot

aclmvh said:
Go to Harbor Freight or some such and get yourself a digital laser thermometer0 $8 at Harbor Freight. Your heads should not get above 150 degrees.
Click to expand...

And if they do ge above 150 degrees?
 
aclmvh

aclmvh

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Re: My engine continues to run hot

WalterJS said:
And if they do ge above 150 degrees?
Click to expand...

Work your way backwards to the water intake. Since you removed the tstats, it could the deflectors in the head- they may be bad or may be blocking the water flow through the head. Have you checked your plugs for signs of water? That would point to a breach in your head gaskets. Do you have a good pee stream when the boat's in the water? If not, that would be a water pump. What about the old tstat housing? Is there corrosion or blockage in there that would keep water from flowing to the cylinders?

Just thinking out loud....
 
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