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.