Is a range from 120 to 150 a normal top cyl to bottom cyl compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.

There should be no more than 15 psi between all cylinders. Usual compression
is frrom 90-110 psi with 80 psi being the minimum on older engines.


"mwaidley" wrote in message
m...
Is a range from 120 to 150 a normal top cyl to bottom cyl compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.

So would you say from past experiences that this could be a really bad
thing, needing ring replacement, head boring, and all that fun
stuff...or is it sometimes just due to lack of use...a frozen ring?
The boat has been sitting stagnent for some time and i think that may
be all that is wronge. $3k for a 17ft bayliner capri, floor is soft
in 2 places, hull is in good condition. This will be my first boat,
but deffinatly not my first engine. I can handle any repair
necessary...but do you think its worth it?



"JSE" wrote in message ...
There should be no more than 15 psi between all cylinders. Usual compression
is frrom 90-110 psi with 80 psi being the minimum on older engines.


"mwaidley" wrote in message
m...
Is a range from 120 to 150 a normal top cyl to bottom cyl compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.

I'ld look around a little bit before getting this one.

--
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Fishing Link Index
www.YumaBassMan.com

webmaster
at
YumaBsssMan
dot
com
"mwaidley" wrote in message
m...
So would you say from past experiences that this could be a really bad
thing, needing ring replacement, head boring, and all that fun
stuff...or is it sometimes just due to lack of use...a frozen ring?
The boat has been sitting stagnent for some time and i think that may
be all that is wronge. $3k for a 17ft bayliner capri, floor is soft
in 2 places, hull is in good condition. This will be my first boat,
but deffinatly not my first engine. I can handle any repair
necessary...but do you think its worth it?



"JSE" wrote in message
...
There should be no more than 15 psi between all cylinders. Usual
compression
is frrom 90-110 psi with 80 psi being the minimum on older engines.


"mwaidley" wrote in message
m...
Is a range from 120 to 150 a normal top cyl to bottom cyl compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.

I think that if it were a stuck ring then it may work it's way loose in a
short time. If you're serious about the boat, I would do this....
1. Put some Marvel mystery oil in al the cylinders and let it set for a
couple hours
2. Have the owner take you out for a short run after that ( about 20 mins or
so)
3. Check the compression again

The value of the boat should stand on it's own. The owner isn't selling you
the engine, if there's something wrong with the engine. Do these 3 things,
then negotiate your deal. Rebuild kits aren't too expensive, but if the
mystery oil doesn't free it up, there may be signifiant damage to the
cylinder walls too.

"Bob La Londe" wrote in message
...
I'ld look around a little bit before getting this one.

--
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Fishing Link Index
www.YumaBassMan.com

webmaster
at
YumaBsssMan
dot
com
"mwaidley" wrote in message
m...
So would you say from past experiences that this could be a really bad
thing, needing ring replacement, head boring, and all that fun
stuff...or is it sometimes just due to lack of use...a frozen ring?
The boat has been sitting stagnent for some time and i think that may
be all that is wronge. $3k for a 17ft bayliner capri, floor is soft
in 2 places, hull is in good condition. This will be my first boat,
but deffinatly not my first engine. I can handle any repair
necessary...but do you think its worth it?



"JSE" wrote in message
...
There should be no more than 15 psi between all cylinders. Usual
compression
is frrom 90-110 psi with 80 psi being the minimum on older engines.


"mwaidley" wrote in message
m...
Is a range from 120 to 150 a normal top cyl to bottom cyl
compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a
boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.

Ill run the boat for a bit and see if the ring frees its self with the
Marvel mystery oil, if not. Ill just rebuild :-) Any suggestions on
where to go for a rebuild kit, if i need to?


Thanks for all the great advise!!
MW



"JSE" wrote in message ...
I think that if it were a stuck ring then it may work it's way loose in a
short time. If you're serious about the boat, I would do this....
1. Put some Marvel mystery oil in al the cylinders and let it set for a
couple hours
2. Have the owner take you out for a short run after that ( about 20 mins or
so)
3. Check the compression again

The value of the boat should stand on it's own. The owner isn't selling you
the engine, if there's something wrong with the engine. Do these 3 things,
then negotiate your deal. Rebuild kits aren't too expensive, but if the
mystery oil doesn't free it up, there may be signifiant damage to the
cylinder walls too.

"Bob La Londe" wrote in message
...
I'ld look around a little bit before getting this one.

--
Public Fishing Forums
Fishing Link Index
www.YumaBassMan.com

webmaster
at
YumaBsssMan
dot
com
"mwaidley" wrote in message
m...
So would you say from past experiences that this could be a really bad
thing, needing ring replacement, head boring, and all that fun
stuff...or is it sometimes just due to lack of use...a frozen ring?
The boat has been sitting stagnent for some time and i think that may
be all that is wronge. $3k for a 17ft bayliner capri, floor is soft
in 2 places, hull is in good condition. This will be my first boat,
but deffinatly not my first engine. I can handle any repair
necessary...but do you think its worth it?



"JSE" wrote in message
...
There should be no more than 15 psi between all cylinders. Usual
compression
is frrom 90-110 psi with 80 psi being the minimum on older engines.


"mwaidley" wrote in message
m...
Is a range from 120 to 150 a normal top cyl to bottom cyl
compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a
boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.

www.mercruiserparts.com or www.stemtostern.com should give you a good start.
Joe



"mwaidley" wrote in message
om...
Ill run the boat for a bit and see if the ring frees its self with the
Marvel mystery oil, if not. Ill just rebuild :-) Any suggestions on
where to go for a rebuild kit, if i need to?


Thanks for all the great advise!!
MW



"JSE" wrote in message ...
I think that if it were a stuck ring then it may work it's way loose in
a
short time. If you're serious about the boat, I would do this....
1. Put some Marvel mystery oil in al the cylinders and let it set for a
couple hours
2. Have the owner take you out for a short run after that ( about 20
mins or
so)
3. Check the compression again

The value of the boat should stand on it's own. The owner isn't selling
you
the engine, if there's something wrong with the engine. Do these 3
things,
then negotiate your deal. Rebuild kits aren't too expensive, but if the
mystery oil doesn't free it up, there may be signifiant damage to the
cylinder walls too.

"Bob La Londe" wrote in message
...
I'ld look around a little bit before getting this one.

--
Public Fishing Forums
Fishing Link Index
www.YumaBassMan.com

webmaster
at
YumaBsssMan
dot
com
"mwaidley" wrote in message
m...
So would you say from past experiences that this could be a really
bad
thing, needing ring replacement, head boring, and all that fun
stuff...or is it sometimes just due to lack of use...a frozen ring?
The boat has been sitting stagnent for some time and i think that
may
be all that is wronge. $3k for a 17ft bayliner capri, floor is
soft
in 2 places, hull is in good condition. This will be my first boat,
but deffinatly not my first engine. I can handle any repair
necessary...but do you think its worth it?



"JSE" wrote in message
...
There should be no more than 15 psi between all cylinders. Usual
compression
is frrom 90-110 psi with 80 psi being the minimum on older
engines.


"mwaidley" wrote in message
m...
Is a range from 120 to 150 a normal top cyl to bottom cyl
compression
for a murcury force 120? 30 PSI is a huge range. Before i buy
a
boat
i thought i would check and see if anyone knew if this was
normal or
not? Its a bigger range than i am used to seeing.

the force motors are bad for the piston coming apart between the two
rings. little chunks will break off and affect the compression.
eventually it will let go and then you are forced to do a rebuild
including boring and piston replacement. if you catch it soon enough
you may get away with just a piston replacement. if you can talk to a
shop that rebuilds outboards they may have an example lying around.


mwaidley wrote:
So would you say from past experiences that this could be a really bad
thing, needing ring replacement, head boring, and all that fun
stuff...or is it sometimes just due to lack of use...a frozen ring?
The boat has been sitting stagnent for some time and i think that may
be all that is wronge. $3k for a 17ft bayliner capri, floor is soft
in 2 places, hull is in good condition. This will be my first boat,
but deffinatly not my first engine. I can handle any repair
necessary...but do you think its worth it?



"JSE" wrote in message ...

There should be no more than 15 psi between all cylinders. Usual compression
is frrom 90-110 psi with 80 psi being the minimum on older engines.


"mwaidley" wrote in message
. com...

Is a range from 120 to 150 a normal top cyl to bottom cyl compression
for a murcury force 120? 30 PSI is a huge range. Before i buy a boat
i thought i would check and see if anyone knew if this was normal or
not? Its a bigger range than i am used to seeing.