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AQ140A running hot? Advice needed

T

taffkid

Member
Greetings. I have recently aquired a 1978 Chrysler Sport Fury with an AQ140A engine on a 280 outdrive. The boat has two temperature gauges. One is on the dash and does not have numbers, only C---H. The other is mounted under the port rear seat facing forward and has numbers. The sender for the seat-mounted gauge is in the port side of the engine approximately under the forward carburetor. I can't find the sender for the dash gauge.

When we run at or near plane the dash gauge climbs from center to about 1/4 inch from the H mark. The rear gauge never goes above 150-160 degrees Fahrenheit. When we idle or run slow the dash gauge slowly drops to center, but the seat gauge stays the same.

I have felt around the engine and everything is cool or warm (but not too warm to keep your hand on) except for the valve cover which is very hot. I can't keep my hand on it for more than a second or less. I have water flowing through the sea-water strainer and out the exhaust, and there is coolant in the fresh water side.

My questions are, is the valve cover supposed to be too hot to touch? And why does the rear gauge never climb to operating temperature but the front gauge appears to show a hot condition?

Any and all advice is appreciated.
 
If the cam is throwing oil on the underside of the V/C it will be hot as oil temp is always warmer then engine temp. Many guages and senders are not compatible with each other, this may be the case.
 
I was thinking the same thing, however, how hot is too hot up there? All of my previous boats have been outboards and that much heat anywhere on the engine would be very bad.


I plan on replacing the gauges and senders if I can find compatible parts.
 
I think it is hotter than that. I will be servicing the cooling system components. Does anyone know where I can get the proper sending units for oil and temperature gauges? I can't find them in the Sierra catalogue or the Volvo Penta Store site.
 
The gauge under the seat is wired. I haven't traced the dash gauge yet. Does anyone know where I can get sending units for oil and temp gauges? I want to switch to a mechanical oil pressure gauge.
 
The boat has a volt meter with a needle that stays in the middle of the gauge when the engine is on. It looks normal.
 
Last edited:
taffkid said:
The boat has a volt meter with a needle that stays in the middle of the gauge when the engine is on. It looks normal.
Click to expand...

Years ago I had a boat with an AQ140A. It came with an instrument panes that had the "charge" red light (no volt meter), the low oil pressure red light (no oil pressure gauge), and the red/green coolant temperature gauge. For just over $100 I intalled a proper volt meter, an oil pressure gauge and a coolant temperature gauge, all of them Faria if I recall correctly. It wasn't an expensive upgrade, and it helped me to monitor what was going on with the engine.

http://www.faria-instruments.com/
 
Re: AQ140A running hot? **Possibly solved**

I pulled the fresh and sea water cooling systems apart and found that they were being held together by silicone and various types of gasket maker. Needless to say, the silicone and gasket maker pieces have worked their way into the heat exchanger and partially plugged it. The impeller was a little rough and the hose connection was quite corroded. Once I get all the parts together, including proper gaskets and seals, I will put it all together and see what happens.

The good news is that water flow through the manifold, oil cooler, out-drive, block, and various pipes looks fine.

Hopefully this will solve the heating problem.
 
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