"I have done just about everyt
"I have done just about everything I can think of to address this condition. I need help. My starboard riser is much hotter than the port riser. I can hold my hand on the starboard side about 3-4 seconds, port side is cool. T-stat housing discharging hot water out starboard side and cool water out port side. Some Facts:
1998 Mercruiser 5.0L carburated Alpha 1 Gen 2
brackish water use
RWC
Original Failure - mostly plugged starboard exhaust manifold resrticted water flow on starboard side manifold, spacer, riser. Melted/burned all rubber parts on/in the starboard exhaust components. Engine never overheated always runs 165-170F.
Actions Taken - replaced ex. manifolds, spacers, and risers as well as all melted/burned parts. Also replaced circulating pump (it was weeping out the seal hole) and T-stat. Upon testing the starboard riser did not burn or melt the rubber components but it was uncomfortably hot to the touch while the port side was cool.
Further actions - replace raw water pump (full kit including pump housing). Old impeller looked and felt in good condition but replaced anyway. Found metal backing plate from melted flappers in exhaust passage of outdrive upper housing. Upon testing same problem hot to touch starboard riser.
On muffs the water flow from exhaust are roughly equal port vs. starboard but the port exhaust water is cool and starboard is too hot to keep hand in stream. This can be traced back to the t-stat housing, it is hot on starboard side and cool on port side.
Further, Further Actions - replace t-stat housing old housing is rough with rust. Testing on muffs and later in water both result in uncomfortably hot (again to the touch) starboard riser. While on muffs the water flows are again equal but hot on starboard and cool on port.
I have since run the boat on the water for about 3-4 hours and at all rpms and boat speeds the riser remains consistenly hot. Engine temp always solid at just under 170.
T-stat housing is putting out hot water on one side and cool water on the other side. Housing is the open 4 hose type, no check valves/balls. part# 860256-C3. It appears that the hot engine water and the cool bypass water are not mixing prior to discharging out the respective sides of the housing.
What could cause this or is this temperature difference between port and starboard water discharge condsidered normal?
Thanks,
Mike"
"I have done just about everything I can think of to address this condition. I need help. My starboard riser is much hotter than the port riser. I can hold my hand on the starboard side about 3-4 seconds, port side is cool. T-stat housing discharging hot water out starboard side and cool water out port side. Some Facts:
1998 Mercruiser 5.0L carburated Alpha 1 Gen 2
brackish water use
RWC
Original Failure - mostly plugged starboard exhaust manifold resrticted water flow on starboard side manifold, spacer, riser. Melted/burned all rubber parts on/in the starboard exhaust components. Engine never overheated always runs 165-170F.
Actions Taken - replaced ex. manifolds, spacers, and risers as well as all melted/burned parts. Also replaced circulating pump (it was weeping out the seal hole) and T-stat. Upon testing the starboard riser did not burn or melt the rubber components but it was uncomfortably hot to the touch while the port side was cool.
Further actions - replace raw water pump (full kit including pump housing). Old impeller looked and felt in good condition but replaced anyway. Found metal backing plate from melted flappers in exhaust passage of outdrive upper housing. Upon testing same problem hot to touch starboard riser.
On muffs the water flow from exhaust are roughly equal port vs. starboard but the port exhaust water is cool and starboard is too hot to keep hand in stream. This can be traced back to the t-stat housing, it is hot on starboard side and cool on port side.
Further, Further Actions - replace t-stat housing old housing is rough with rust. Testing on muffs and later in water both result in uncomfortably hot (again to the touch) starboard riser. While on muffs the water flows are again equal but hot on starboard and cool on port.
I have since run the boat on the water for about 3-4 hours and at all rpms and boat speeds the riser remains consistenly hot. Engine temp always solid at just under 170.
T-stat housing is putting out hot water on one side and cool water on the other side. Housing is the open 4 hose type, no check valves/balls. part# 860256-C3. It appears that the hot engine water and the cool bypass water are not mixing prior to discharging out the respective sides of the housing.
What could cause this or is this temperature difference between port and starboard water discharge condsidered normal?
Thanks,
Mike"