V 90 Overheat at Idle

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Bandit925

Recruit
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Apr 8, 2012
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I have an 1985 Evinrude V90. I have had it for 9 years and had to have it rebuilt last year. It ran good all summer last year. I took it out of storage and launched it at a site with a long no wake area. Got good water out of the indicator and everything seamed fine but engine overheated while minimum forward speed in no wake. I shut it down and we trolled out of no wake, let engine cool, restarted and ran the engine with no overheating. When we returned I made sure we were running slightly above minimum forward speed in the no wake and again no overheating.

Is there a reason that engine would overheat with long run at minimum forward speed?
 
AEROCOOK

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
Re: V 90 Overheat at Idle

How strong was the tell tale stream at low RPM? Can we assume that an new waterpump impellor was installed as part of the rebuild last year?
 
Faztbullet

Faztbullet

Supreme Mariner
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Mar 2, 2008
Messages
15,616
Re: V 90 Overheat at Idle

Got good water out of the indicator
Click to expand...
This dont mean nothing on the V-4 as indicator is before the t-stats and poppets,its just doing it job ...telling that pump is pumping as it tells you nothing about cooling.
 
T

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: V 90 Overheat at Idle

If the impeller and/or water pump housing is worn out, then it will not pump well at low speeds.
Time to service it if it has not been done recently.
 
Silvertip

Silvertip

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Sep 22, 2003
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28,762
Re: V 90 Overheat at Idle

Theremostat stuck shut at slow speeds causes overheating. A bypass poppet stuck shut causes overheating at higher speeds. It is not uncommon to have a thermostat stick during long term storate. You can either replace it, or if it now seems to operate properly then it was simply a little slow to wake up. However, overheat ae never good for an engine so I would replace both the thermostat and the poppet valve. If you have not serviced the water pump then it too needs to be done. That should have been done when the engine was rebuilt if the shop had any sense of responsibility.
 
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Bandit925

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Apr 8, 2012
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Re: V 90 Overheat at Idle

Thanks for the information. The water pump impeller and housing was replaced, I do not know about the thermostats and will be changing them.
 
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