i have a 1998 9.9 gamefisher i have some question i hop i can get some
help with.
1. approx how much compression should it have?
2. can you get an accurate reading by just pulling the rope? does that
spin it faste enough, long enough?
3. if one cyl is 30# less then the other, what might be the probable
causes be after head gasket has been eliminated? the cy wall looks
fine, no scratches, abrasions

i sure appreciate any help on this, i have really liked the
'spunkyness' of this motor and it ran well the past few years. my son
overheated it by backing in reverse for an extended period of time
while motoring around a small lake inlet.

thanks in advance.. -gary

"gary" wrote in message
ups.com...
i have a 1998 9.9 gamefisher i have some question i hop i can get some
help with.

1. approx how much compression should it have?
Depends on the engine, and specs. My 7.5 Gamefisher
has about 85 Psi. I think 60-ish is probably the low end.

2. can you get an accurate reading by just pulling the rope?
Yes. If you have a good compression gague, it will have a
good one-way shrader vale where you can keep puling like
hell, and it will record the "highest" reading of all the pulls.

does that
spin it faste enough, long enough?

Yes. Its not a "long enough" thing anyhow.


3. if one cyl is 30# less then the other, what might be the probable
causes be after head gasket has been eliminated? the cy wall looks
fine, no scratches, abrasions

Craked piston ring, or "stuck" piston ring - very common.
Since people seem to love to use that ****ty-ass petroleum
based 2-stroke oil which causes massive carbon build-up,
it tends to glue the piston rings into the grooves of the piston.
I'd almost bet on it.


i sure appreciate any help on this, i have really liked the
'spunkyness' of this motor and it ran well the past few years. my son
overheated it by backing in reverse for an extended period of time
while motoring around a small lake inlet.

That should not have overheated it - what makes you think
it was overheated? Was it like melt-down overheated, or
just hot-hot? "Overheated" (meltdown style) usually means
burning paint smell, melting wires, stops running, seizure, and
"oh ****, how do I get out of here, and what do I tell the ole lady".

Since you got the head off, might try to get a can of Gumout
choike and carb cleaner, and take that little red nozzle tube
and spray down into the edge of the pistons real good to
try to get it down into the ring groves. Make SURE to wear
goggles - getting Gumout in the eyes will temporarily blind
you, and you will need to craw to a water facet and flush for
min 1/2 hour. (can you tell I been there/done that?)






thanks in advance.. -gary

thanks wiz and cwm, i got a bit rejunivated at cwm's suggestion it
might be a warped head, may still be... gasket sure showed no signs
of leakage. will check it out thourghly before tear-down. will work
the gum-out angle and put new head-gasket on and run some more. how
about add a little marvel or like to gas to work on a ring if it be
that?
hot or o**** hot? just hot, super hot steam coming from thermostat
discharge. expected to find impeller wore to shreds upon take off but
it looked fine. couldn't relate that to over heat. thought it must be
the backing against the water inlets on the lower shaft. hum??
petrolem based oil? you talking as opposed to synthetic? don't know
if i've even seen synthetic 2 cycle oil.
will let you know on the gum-out, head gasket test. will use goggles,
also btdt. thanks for your input.. -gary




Overheated? If you are sure you have eliminated the head gasket, it's
probably a
warped head. If it's not too bad, an automotive machine shop can
probably fix
it. If one cylinder is 30# different, the head likely either needs
resurfacing
or replacing.

CWM



Mr Wizzard wrote:
"gary" wrote in message
ups.com...
i have a 1998 9.9 gamefisher i have some question i hop i can get some
help with.

1. approx how much compression should it have?
Depends on the engine, and specs. My 7.5 Gamefisher
has about 85 Psi. I think 60-ish is probably the low end.

2. can you get an accurate reading by just pulling the rope?
Yes. If you have a good compression gague, it will have a
good one-way shrader vale where you can keep puling like
hell, and it will record the "highest" reading of all the pulls.

does that
spin it faste enough, long enough?

Yes. Its not a "long enough" thing anyhow.


3. if one cyl is 30# less then the other, what might be the probable
causes be after head gasket has been eliminated? the cy wall looks
fine, no scratches, abrasions

Craked piston ring, or "stuck" piston ring - very common.
Since people seem to love to use that ****ty-ass petroleum
based 2-stroke oil which causes massive carbon build-up,
it tends to glue the piston rings into the grooves of the piston.
I'd almost bet on it.


i sure appreciate any help on this, i have really liked the
'spunkyness' of this motor and it ran well the past few years. my son
overheated it by backing in reverse for an extended period of time
while motoring around a small lake inlet.

That should not have overheated it - what makes you think
it was overheated? Was it like melt-down overheated, or
just hot-hot? "Overheated" (meltdown style) usually means
burning paint smell, melting wires, stops running, seizure, and
"oh ****, how do I get out of here, and what do I tell the ole lady".

Since you got the head off, might try to get a can of Gumout
choike and carb cleaner, and take that little red nozzle tube
and spray down into the edge of the pistons real good to
try to get it down into the ring groves. Make SURE to wear
goggles - getting Gumout in the eyes will temporarily blind
you, and you will need to craw to a water facet and flush for
min 1/2 hour. (can you tell I been there/done that?)






thanks in advance.. -gary