I am new to boating but pretty up to speed on dry land engine stuff.
I have fallen heir to a Mirrocruiser 25' (1980 Cruisers Inc) that I am
going to have to rebuild. The hull is in really good shape and I can
see a lot stuff has already been replaced - alternator, starter, prop.
Everything else seems to work - the remote etc
The Mercruiser lump has been lying uncovered for a few months and is
partially siezed due to rainwater getting in thru the carb (I am
soaking this thing neat WD40 in the hope I can slacken it off). The
guy had left the flame arrestor/filter assembly off.
If this "unsiezing" exercise is a failure, can I use use a Chevy 350
lump - the block and heads seem to be the same - just the oil pan is an
obvious difference. Can I swap the bits over and make it a equal to a
Marine version? The stern drive is a M/C - the one with the loop on
the top (pre-Alpha One). The cooling system is closed system with a
seawater pump driven by a belt on the front and has a hull intake just
forward of the engine. Does this mean that I can ignore the sterndrive
pump?
Any help is greatly appreciated - I am not looking for a Rolls Royce
rocket boat - I just want chug about the lake and go fishing!

If the replacement lump is pre 1987 out of a truck The lumps should lump
together pretty well. Be advised that non marine lumps might rust out if
used in salt water.
Jim

"Poolboy" wrote in message
oups.com...
I am new to boating but pretty up to speed on dry land engine stuff.
I have fallen heir to a Mirrocruiser 25' (1980 Cruisers Inc) that I am
going to have to rebuild. The hull is in really good shape and I can
see a lot stuff has already been replaced - alternator, starter, prop.
Everything else seems to work - the remote etc
The Mercruiser lump has been lying uncovered for a few months and is
partially siezed due to rainwater getting in thru the carb (I am
soaking this thing neat WD40 in the hope I can slacken it off). The
guy had left the flame arrestor/filter assembly off.
If this "unsiezing" exercise is a failure, can I use use a Chevy 350
lump - the block and heads seem to be the same - just the oil pan is an
obvious difference. Can I swap the bits over and make it a equal to a
Marine version? The stern drive is a M/C - the one with the loop on
the top (pre-Alpha One). The cooling system is closed system with a
seawater pump driven by a belt on the front and has a hull intake just
forward of the engine. Does this mean that I can ignore the sterndrive
pump?
Any help is greatly appreciated - I am not looking for a Rolls Royce
rocket boat - I just want chug about the lake and go fishing!

Thanks Jim,
This was a sal****er boat - now it will be a fresh water toy. Any
advise about the stern drive water pump - should I just ignore it since
it has a belt driven raw water unit drawing in from the botton of the
boat?
The thing came with a couple of deep cycle batteries - I thought a few
heavy starts would wreck them - should I fit a high CCA 600+ regular
sealed autobattery?

Jim wrote:
If the replacement lump is pre 1987 out of a truck The lumps should lump
together pretty well. Be advised that non marine lumps might rust out if
used in salt water.
Jim

"Poolboy" wrote in message
oups.com...
I am new to boating but pretty up to speed on dry land engine stuff.
I have fallen heir to a Mirrocruiser 25' (1980 Cruisers Inc) that I am
going to have to rebuild. The hull is in really good shape and I can
see a lot stuff has already been replaced - alternator, starter, prop.
Everything else seems to work - the remote etc
The Mercruiser lump has been lying uncovered for a few months and is
partially siezed due to rainwater getting in thru the carb (I am
soaking this thing neat WD40 in the hope I can slacken it off). The
guy had left the flame arrestor/filter assembly off.
If this "unsiezing" exercise is a failure, can I use use a Chevy 350
lump - the block and heads seem to be the same - just the oil pan is an
obvious difference. Can I swap the bits over and make it a equal to a
Marine version? The stern drive is a M/C - the one with the loop on
the top (pre-Alpha One). The cooling system is closed system with a
seawater pump driven by a belt on the front and has a hull intake just
forward of the engine. Does this mean that I can ignore the sterndrive
pump?
Any help is greatly appreciated - I am not looking for a Rolls Royce
rocket boat - I just want chug about the lake and go fishing!

Belt driven water pump leads me to think you have fresh water cooling. If it
was factory done the only thing that saw salt was the risers. Toss em and
buy new ones. Alternately, you could opt for a more modern bolt on exhaust
system for more $$$. Replace batteries as needed. NBD. The drive isn't worth
messing with and the water pump doesn't do anything, so leave it alone. When
the drive breaks buy a used alpha 1, which will bolt up nicely.
Jim
"Poolboy" wrote in message
oups.com...
Thanks Jim,
This was a sal****er boat - now it will be a fresh water toy. Any
advise about the stern drive water pump - should I just ignore it since
it has a belt driven raw water unit drawing in from the botton of the
boat?
The thing came with a couple of deep cycle batteries - I thought a few
heavy starts would wreck them - should I fit a high CCA 600+ regular
sealed autobattery?

Jim wrote:
If the replacement lump is pre 1987 out of a truck The lumps should lump
together pretty well. Be advised that non marine lumps might rust out if
used in salt water.
Jim

"Poolboy" wrote in message
oups.com...
I am new to boating but pretty up to speed on dry land engine stuff.
I have fallen heir to a Mirrocruiser 25' (1980 Cruisers Inc) that I am
going to have to rebuild. The hull is in really good shape and I can
see a lot stuff has already been replaced - alternator, starter, prop.
Everything else seems to work - the remote etc
The Mercruiser lump has been lying uncovered for a few months and is
partially siezed due to rainwater getting in thru the carb (I am
soaking this thing neat WD40 in the hope I can slacken it off). The
guy had left the flame arrestor/filter assembly off.
If this "unsiezing" exercise is a failure, can I use use a Chevy 350
lump - the block and heads seem to be the same - just the oil pan is an
obvious difference. Can I swap the bits over and make it a equal to a
Marine version? The stern drive is a M/C - the one with the loop on
the top (pre-Alpha One). The cooling system is closed system with a
seawater pump driven by a belt on the front and has a hull intake just
forward of the engine. Does this mean that I can ignore the sterndrive
pump?
Any help is greatly appreciated - I am not looking for a Rolls Royce
rocket boat - I just want chug about the lake and go fishing!

Or just about any other small block. Pre 86 will be easier. The carb and
alternator are about the only truly marine things about it. Even the oil
pan doesn't really matter. That size boat you may have room for a big block
as well. But you would need more brackets and things.

The fiberglass usually holds up pretty well on all boats. It's the
encapsulated wood that causes trouble. Check the floor and transom
carefully for signs of wood rot. Some people will actualy drill small test
holes in places to see whatthey get out. If you do that just fill the hole
back up with epoxy. If there is rot you might want to think carefully about
putting any money in it.

The outdrive pump feeds in at a hose on the inside half of the transom
bracket that it is mounted with. Some boats with alternate raw water pumps
still used the outdrive pump for cooling the exhaust. If the pickup ports
are open on the outdrive you might want to see if that hose is there or it
looks like anything was hooked to it. You could always split the outdrive
and see if the impeller is still in the pump. Also I'd be worried about the
condition of the heat exchanger. If the closed system is shot you may want
to convert to raw water cooling. Particularly if you're going to be in
fresh water from now on. Also check the exhaust system. They corrode out
as well.

"Poolboy" wrote in message
oups.com...
I am new to boating but pretty up to speed on dry land engine stuff.
I have fallen heir to a Mirrocruiser 25' (1980 Cruisers Inc) that I am
going to have to rebuild. The hull is in really good shape and I can
see a lot stuff has already been replaced - alternator, starter, prop.
Everything else seems to work - the remote etc
The Mercruiser lump has been lying uncovered for a few months and is
partially siezed due to rainwater getting in thru the carb (I am
soaking this thing neat WD40 in the hope I can slacken it off). The
guy had left the flame arrestor/filter assembly off.
If this "unsiezing" exercise is a failure, can I use use a Chevy 350
lump - the block and heads seem to be the same - just the oil pan is an
obvious difference. Can I swap the bits over and make it a equal to a
Marine version? The stern drive is a M/C - the one with the loop on
the top (pre-Alpha One). The cooling system is closed system with a
seawater pump driven by a belt on the front and has a hull intake just
forward of the engine. Does this mean that I can ignore the sterndrive
pump?
Any help is greatly appreciated - I am not looking for a Rolls Royce
rocket boat - I just want chug about the lake and go fishing!