Manifold Temperatures

[johnkom]

What should the manifold temperatures be under?? I can put my hand on them but can't leave it there. Is that cool enough? Is there an actual temperature value? I plan on taking my inferred temp gun with me next time and get an actual value. Engine is a 233 Mercruiser.

 

[harringtondav]

I assume you're talking about the exhaust risers and elbows (?). I wouldn't get my hand close to any hot exhaust manifold. I've never seen a surface temp. spec. in my engine manual for the risers/elbows. My 4.3 is well cooled, but these risers and elbows can get uncomfortable to the touch.

I'd be more concerned about the actual engine cooling jacket water temperature. Does your dash temp. gage indicate a problem? When you have the boat on muffs and at temp., is there a good exhaust water outflow from the gimbal hsg. relief ports?

 

[AShipShow]

If your boat is raw water cooled, the risers can get uncomfortable to the touch when your just sitting there idling (could also be a difference from one side to the other), but they should tend to cool off when you start moving in the water... The higher shaft speed through the outdrive will make the impellar pump more water.

If they are too hot to touch while underway or your gauge shows high then you might want to start looking into the condition of your manifolds/risers.

 

[Scott Danforth]

since 150 is the scald temp, your manifolds are around 150-160 if you can put your hand on it at all without burning

your fine,