Chrysler 440 Running Hot

brl96

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Jul 14, 2013
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20
Guys,motor

I recently replaced my inboard with a chrysler 440 motor (1976 vintage). The cooling system is a raw water system. The motor has a sherwood water pump that pumps lake water to the thermostat housing. From there is goes to the exhaust manifolds and out the boat. There is also a bi-directional circulating water pump that draws from the same suction hose as the sherwood pump. That pump circulates water through the engine out the thermostat. When starting the motor, temperature ran up to about 170F (142F thermostat). I turned it off and removed the thermostat housing. Then started, the sherwood pump had good flow. The circulating water pump was dry. I removed the pump and it was dry but looked fine. I confirmed the suction hose was unblocked. Does this pump need to be primed to pump? I am at a lost on why it is not moving water.

Any ideas.
 

Bondo

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Apr 17, 2002
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Does this pump need to be primed to pump? I am at a lost on why it is not moving water.

Ayuh,.... Welcome Aboard,.... Donno yer system, but generally speakin',....

The raw water pump should feed the system, 'n the circulatin' pump,....

Never seen both pumps draw from a hose, or the same hose,...

The circulatin' pump is a circulator, which needs to be fed water to move any water, it Can't suck water, just push water,....

Pictures of yer set up will no doubt be helpful,...
 

brl96

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Jul 14, 2013
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I will try to get a picture posted but it appears something is not hooked up correctly. My raw water pump goes directly from the suction of the lake to the top of the thermostat. From there it branches to the oil and the transmission oil coolers. From there thru the exhausts and out the boat. I do not have a heat exchanger. i have the circulating water pump suction also hooked up to the same suction line on the bottom of the boat. I see from the Chrylser 330 manual it should be a closed system. Is this the only way to hook it up?
 

Bondo

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Ayuh,..... The circulatin' pump should be fed from the t-stat housin',....

I'm guessin' ya need the proper t-stat housin' for a raw water system,....

Yer Right, yer system is plumbed all wrong,....
 

brl96

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Jul 14, 2013
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20
Thanks for the help. You pointed me in the correct direction. The raw water pump actually keeps the engine full of water (like a keep fill system). I had my hoses reversed and my raw water pump installed upside down. Thanks again.
 
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