warm risers

[bushwood]

[FONT=Verdana, Arial, Helvetica]Posted - Oct 17 2010 : 14:28:35[/FONT] [FONT=Verdana, Arial, Helvetica][FONT=Verdana, Arial, Helvetica]Twin Chrysler 440s, FWC. When I push the engines over 2400, lots of steam out the transom. Stbd engine gauge climbs from 170-190. When at idle, I can feel the exhaust water exiting is significantly warmer than the port engine exhaust water.

I can feel a temp difference on port engine risers vs. stbd engine risers. Per my infrared temp gun, stbd engine risers are 100 degrees vs. stbd engine risers at 88 degrees. I'm not losing any coolant. My risers are only 3 yrs old on both engines. Pull risers and re-gasket? I am seeing, what appears to be good water flow, out the exhaust ports (at dock). But like I said, the water is warmer as is the top of the riser itself.

Thanks
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[loid58]

If you're getting steam, then the risers are clogged up, and not allowing proper flow. The water is betting boiled inside the risers, thus the steam. If they are only 3 yrs old take them to a radiator shop and have them boiled out and pressure tested to see if they are rotted out, then try them out.Also do that to the manifolds they could be on their last legs also.

 

[bushwood]

I think I fixed riser issue. Water hose connected to riser had abnormal-pinching bend that possible slowed the flow rate. I put a new hose on and riser feels good and shows cool temp on infrared gun.
Next issue, as I shot engine with temp gun, I noticed inboard exhaust manifold was OK in temp, but end cap was very HOT. What would cause this if manifold was within temp spec? FWC Chrysler 440.
Thanks

 

[tolly_family]

Normal as the end cap is not water cooled and is exposed to the exhaust.

Dan

 

[WoodieMan]

Tolly is correct. In fact, older vintages have a tube running from there picking up heat to operate the choke.