'97 7.4L Bravo One Overheat Problem

gibbywmu2000

Petty Officer 2nd Class
Joined
Apr 20, 2008
Messages
116
Everyone,

Been reading some threads on overheat since last night. Boat started overheating this weekend, not sure what the real issue is yet. I have not yet checked the water pump impeller, although it was just replaced Memorial Day weekend and has been working fine since. The past 3 times that has failed, no water was getting through the cooling system at all, and it currently water is in fact coming out of the exhaust ports. Temp keeps climbing to over 200F and cannot figure it out. Pulled thermostat out, but I did not do the stove test (dont have internet at cottage and forgot how to test this). Could a water passage be blocked or something? Thermostat is several years old, could that be bad? If someone could point me in the right direction, sure would appreciate it. Just doesn't seem like the impeller could be bad, if there is water coming out of my thru hull exhaust? No idea. Help appreciated, if it sounds like a thermostat I can just change that myself in 5 minutes! This impeller is a pain in the butt to replace, you have to remove the fuel filter and fuel pump to get to it.
 

MarkSee

Lieutenant Junior Grade
Joined
Sep 10, 2010
Messages
1,172
Re: '97 7.4L Bravo One Overheat Problem

If you put your hands on the exhaust risers, are they real hot where you have to pull your hand off?

Just trying to get an idea.........

Mark
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,103
Re: '97 7.4L Bravo One Overheat Problem

Everyone,

Been reading some threads on overheat since last night. Boat started overheating this weekend, not sure what the real issue is yet. I have not yet checked the water pump impeller, although it was just replaced Memorial Day weekend and has been working fine since. The past 3 times that has failed, no water was getting through the cooling system at all, and it currently water is in fact coming out of the exhaust ports. Temp keeps climbing to over 200F and cannot figure it out. Pulled thermostat out, but I did not do the stove test (dont have internet at cottage and forgot how to test this). Could a water passage be blocked or something? Thermostat is several years old, could that be bad? If someone could point me in the right direction, sure would appreciate it. Just doesn't seem like the impeller could be bad, if there is water coming out of my thru hull exhaust? No idea. Help appreciated, if it sounds like a thermostat I can just change that myself in 5 minutes! This impeller is a pain in the butt to replace, you have to remove the fuel filter and fuel pump to get to it.

Ayuh,.... The manifolds are fed water from the bottom, 'n flow out through the risers,..
As well as the by-pass hoses from the T-stat housin' to the risers...

If the manifold/ risers gaskets/ ports get plugged up/ restricted, you could have yer issue...
 

gibbywmu2000

Petty Officer 2nd Class
Joined
Apr 20, 2008
Messages
116
Re: '97 7.4L Bravo One Overheat Problem

Mark,

Yes, the exhaust risers are so hot I have to pull my hand off........but the water is still getting through the system. You think its the thermostat?
 

MarkSee

Lieutenant Junior Grade
Joined
Sep 10, 2010
Messages
1,172
Re: '97 7.4L Bravo One Overheat Problem

Like Bond-o indicated, probably got some clogging going on there and need to start narrowing it down.

Pulling the risers off and checking them and the gaskets might give some better insight.

Mark
 
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