Replacing merc thermostat housing

Have a 5.7 Merc. carbed that is starting to over heat in the 3900 rpm range,
Alpha drive. Runs fine, 165 degrees, at 3600 revs- needed to plane and and
travel at 18-23 mph. Changed the thermostat to no avail. Noticed the older
type one piece, 6 hose housing is in bad shape. Merc wants 396.00 for a
replacement. Noticed Sierra offers a stainless 4 house housing for 115.00 Can
I use it safely? How important are the houses that run to the elbows? Any
help would be appreciated.

Have you checked the raw water pump? When was the last time the impeller
was replaced? Normally you can clean up the housing and it will be ok.
Check the balls and springs.

The stock housing routes the bypass water straight to the risers. When open
the water leaves the engine and goes to the manifolds then up into the
risers. It's ok to rig it to always go to the manifolds and plug the lines
into the risers.

"FOP NO98" <fopno98.DeleteThis@aol.com> wrote in message
news:20040627131309.03786.00000403@mb-m19.aol.com...
 > Have a 5.7 Merc. carbed that is starting to over heat in the 3900 rpm
range,
 > Alpha drive. Runs fine, 165 degrees, at 3600 revs- needed to plane and
and
 > travel at 18-23 mph. Changed the thermostat to no avail. Noticed the
older
 > type one piece, 6 hose housing is in bad shape. Merc wants 396.00 for a
 > replacement. Noticed Sierra offers a stainless 4 house housing for 115.00
Can
 > I use it safely? How important are the houses that run to the elbows?
Any
 > help would be appreciated.<!-- ~MESSAGE_AFTER~ -->