Mercruiser 454 exhaust steaming ?

[anglosax]

Hi
I have a 454 1990 FWC model and have replaced the exhaust manifolds and risers. I used all new bolts/gaskets [ the green ones used dry] and after retorqueing after heat up, I am still getting some steaming out the exhaust. I can tolerate a slight vapor trail but at 2000 rpm its more than a trail. Question is - should there be any steam at all with a horizontal cylinder exhaust and if I have a riser leak how best to cure it
Thanks

 

[86 century]

Re: Mercruiser 454 exhaust steaming ?

Is the steam coming from the eng compartment or out of the transom.

Some steam is normal
Are your manifolds and risers getting hot to the touch.

 

[dubs283]

Re: Mercruiser 454 exhaust steaming ?

the exhaust manifolds still use sea water for cooling even though you have a closed cooling system

if the sea water is a cooler temp then normal, usually the case this time of year (northern hemisphere) you will definitely get steam

it is normal, and unless you are experiencing runnability issues or other problems i wouldn't be concerned

 

[ENSIGN]

Re: Mercruiser 454 exhaust steaming ?

I agree with dubs,you can also use a infrared temp gun to ease your mind

 

[cr2k]

Re: Mercruiser 454 exhaust steaming ?

When was the impeller last changed?

 

[anglosax]

Re: Mercruiser 454 exhaust steaming ?

the exhaust manifolds still use sea water for cooling even though you have a closed cooling system

if the sea water is a cooler temp then normal, usually the case this time of year (northern hemisphere) you will definitely get steam

it is normal, and unless you are experiencing runnability issues or other problems i wouldn't be concerned

Thanks for the replies - the exhaust water flow is as normal and is around 60-70 deg at the transom. the risers are hand hot to touch after 30 mins and the engine temp stays around 150 deg all as normal . My concerns were based on the prevoius experience of engine damage from leaking riser gaskets and that in southern cal the air temp is usually mild