Overheating Issues

[MBStafford]

I have a 454 Bravo 1. Cools at an idol, but overheats when above 3000 rpm's.
I have changed the impeller, flushed the hoses, and changed the thermostat.
Any other suggestions?

Thanks much!
Mark

 

[WAVENBYE2]

Re: Overheating Issues

Faulty thermostat ?? maybe. Are you running it on muffs or in the water at 3000rpms.?? I have purchased faulty parts before.

 

[seasure1]

Re: Overheating Issues

You haven't mentioned anything about the age of your manifolds and risers. Also check the water inlet from the transom that goes to the back of your water pump. ( the one with the impeller in it)

 

[MBStafford]

Re: Overheating Issues

age of Manifolds/risers are 11 yrs old. Already checked the inlet.

 

[Bondo]

Re: Overheating Issues

age of Manifolds/risers are 11 yrs old.

There's a Good Chance that the passages thru them are getting Restricted......

Pulling,+ Inspecting the Risers is a Cheap,+ Easy task,.......
If they're Good,..... You're out a New Gasket........
If they're Bad,...... replace'm............

 

[MBStafford]

Re: Overheating Issues

No have tried 2 of them.

It cools on muffs at 3000, does not cool at 3000 in the water.

 

[MBStafford]

Re: Overheating Issues

How do you know if the riser is bad?

 

[Bondo]

Re: Overheating Issues

That still says Restriction.............

Start Pulling Hoses,+ See where you've got Good water Flow.......

Was the Complete Waterpump Kit installed, With the New Housing,..??..??.....
Or Just the Impeller,..??

How do you know if the riser is bad?

The Dump Ports might be Plugged,...... They're up inside, on the Out-bound end of the Riser......
There's also usually some build up of Rust,+ Crud where the Manifold,+ Riser Meet too.......

 

[MBStafford]

Re: Overheating Issues

Pulled most hoses, seems to be getting good flow up to thermostat.

new housing, and impeller replaced

Could the water pump on the motor be bad? (becaise it does cool all day under 3000rpms)

 

[Bondo]

Re: Overheating Issues

Anything is Possible,.............. But I Really Doubt it............

The Recurculating Pump really only moves the water while the T-stat is closed........
When it's Open,....... Pressure from the Raw Water Pump is More than enough to work............

Have the Risers been Off,..??..... I don't understand,.."No have tried 2 of them."

 

[MBStafford]

Re: Overheating Issues

Anything is Possible,.............. But I Really Doubt it............

The Recurculating Pump really only moves the water while the T-stat is closed........
When it's Open,....... Pressure from the Raw Water Pump is More than enough to work............

Have the Risers been Off,..??..... I don't understand,.."No have tried 2 of them."

Raw water pump? Can you tell me more about the risers? Can just the risers be replaced?
Thanks again for all your help.
Mark

 

[seasure1]

Re: Overheating Issues

I think you need to remove the risers and check the water passages. If the manifolds and risers are 11 years old.... I think this would be a good place to start. It seems like you covered mostly everything else. You did not mention if it was fresh water or raw water cooled. Stick with it you will fix this!

 

[Don S]

Re: Overheating Issues

Are you boating in salt water or fresh water?