1988 4.3L Cobra running cool

[PaJon]

Does anyone have a flow diagram for the cobra thermostat housing ? I am working on a friends 88 4.3 that won't run over 125 degrees. I checked the temp with a infrared thermometer and show 130 degrees. I pulled the housing and there was no thermostat in it. We ordered one and installed it but I only shows 135 now. If you run the boat and shut it off after it's warmed up, the gauge will show 175 degrees. If you restart right away it will drop to 135 and stay there. It looks like the flow comes in from the raw pump and splits to the engine and a smaller port going to the exhaust. Something doesn't look right, it looks like the exhaust gets very little flow until the thermostat opens. I would have thought it would be the engine getting the reduced flow until the t-stat opens. Any ideas ? I'm lost on this one. I have an 87 cobra but hate to pull the housing just to see if it's the same.

 

[bruceb58]

Are you doing these checks when you are in the water running under load? Your temps are actually pretty darn close to being ideal.

 

[PaJon]

All my checks are with the boat in the water and off the trailer. I can only get 135 degrees with it warmed up and idling. Anything over 1500 rpms makes the temp drop to 110-120, even at full throttle. My 4.3 runs at 160-175 most of the time, even under load of pulling a tube. This is what has me confused,

 

[bruceb58]

My 4.3 runs at 160-175 most of the time, even under load of pulling a tube. This is what has me confused,

That sounds way to high.

You may be working on the wrong boat!

 

[Bulbash]

Under normal condition you must be under 160* ... I would say that 135* is perfect. Also are you sure that your temperature gauge is 100% correct?

 

[PaJon]

That sounds way to high.

You may be working on the wrong boat!

I'll check mine with the infrared this weekend at the lake.

 

[PaJon]

Under normal condition you must be under 160* ... I would say that 135* is perfect. Also are you sure that your temperature gauge is 100% correct?

There's my confusion, I thought 170 was normal operating temp. My friends temp gauge matches my infrared thermometer so I'll have to check mine this weekend while I'm at the lake.

 

[Lou C]

No Title

On the water hose mine will run 16--165 at most. Here is a pic of the water flow...

 

[Lou C]

Its in my dropbox, this idiotic upgrade won' t let me post links or pics correctly....

 

[bruceb58]

Its in my dropbox, this idiotic upgrade won' t let me post links or pics correctly....

Make sure it's in the public folder and use the IMG /IMG commands