Matt wrote:
It was stored with coolant run through (same as i do every year) There
are no metering balls in the housing, and i toolk the entire housing
apart, everything looks good. Hose's are definately not reversed.
Manifolds/Risers are only 3 years old, fresh water use only. I
inspected the riser and looks good.


"jim 0010" wrote in message
...
Matt wrote:
Hi,

I have a 94' Chaparral w/a 5.7L Mercruiser 350MAG. Looking for some
advice on pinpointing a problem. Here's the story:

Last year everything was running fine. Beginning of this season i
had the outdrive/impeller serviced. After dropping it in the water i
noticed that one Riser gets extremely hot. This is def not the
norm. The temp is constant at 160 (thermostat setting). I took off
the entire thermostat housing (everything was fine), replaced the
thermostat, took off the Riser (everything fine), checked the exhaust
flaps (everything fine), and all hoses looked good. I can't figure
out what could be the problem. My two thoughts, either something
happened over the course of the winter, but what? or when the marina
serviced the outdrive something got screwed up. but if it was an
water intake problem wouldn't both risers get really hot?

Any help troubleshooting is greatly appreciated.

Thanks!!



The first thing to be suspicious of is the work that was just done.
Did you store the engine wet or dry? Dry storage can cause excessive
internal rusting. Rust particles could be clogging a riser or the
riser itself has rusted out and clogged. If your engine has metering
balls in the thermostat housing, they could be worn or where they seat
on the housing could be eroded. Is it possible that you have 2 hoses
reversed.

I would go to the water pump and check it carefully, including the part
the copper tube sticks out, of in the upper unit. It might have melted
during an overheat episode. Also make sure the guy used the right
rebuild kit. Make sure the 3/4 diam water hose in the bell housing isn't
kinked or cracked. Make sure you don't have mussels or vegatation
clogging the water pickup vents. Is one manifold much hotter than the
other? Make sure your timing is set correctly. Make sure some broken
impeller pieces aren't blocking the power steering cooler. Are your
exast shutters clacking noticeably?