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Matt[_3_] Matt[_3_] is offline
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First recorded activity by BoatBanter: Jul 2008
Posts: 21
Default Overheating/Steam - Thermo OK/One exhaust Riser hot - Mercruise 5.7 350MAG

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.