I need some help on this. This year when I cranked my 94 5.7
Mercruiser, I noticed a small water leak on the front of the motor.
I'm not a mechanic but it looks like it is near the water pump. After
letting it run for a while on a water hose adapter, the temp stayed
under 150 and everything looked o.k. to take the boat out for a run on
the 4th with the family. On the lake everything seemed o.k. with power
other than when we were pulling a tube, the power seemed a little off
gunning it out of the hole. Two days later I took it out again and
this time the power was way off. The boat , a 23 foot larson 220,
won't even get on plane. It seems to miss but all of the plugs are
firing when I did a spark test. At idle it seems fine but the engine
still seems to run like its missing a bit. I'm about to check the
timing next. The Oil pressure and temperature and normal. I did have
about 5 to 10 gallons of 10 month old gas in the tank before I filled
it up with 89 octane at the pump. I checked the oil and it looked o.k.
too.

Thanks for all you help,

Tim

Do a compression test.

Tim Tisdale wrote:

I need some help on this. This year when I cranked my 94 5.7
Mercruiser, I noticed a small water leak on the front of the motor.
I'm not a mechanic but it looks like it is near the water pump. After
letting it run for a while on a water hose adapter, the temp stayed
under 150 and everything looked o.k. to take the boat out for a run on
the 4th with the family. On the lake everything seemed o.k. with power
other than when we were pulling a tube, the power seemed a little off
gunning it out of the hole. Two days later I took it out again and
this time the power was way off. The boat , a 23 foot larson 220,
won't even get on plane. It seems to miss but all of the plugs are
firing when I did a spark test. At idle it seems fine but the engine
still seems to run like its missing a bit. I'm about to check the
timing next. The Oil pressure and temperature and normal. I did have
about 5 to 10 gallons of 10 month old gas in the tank before I filled
it up with 89 octane at the pump. I checked the oil and it looked o.k.
too.

Thanks for all you help,

Tim

I need some help on this. This year when I cranked my 94 5.7
Mercruiser, I noticed a small water leak on the front of the motor.
I'm not a mechanic but it looks like it is near the water pump. After
letting it run for a while on a water hose adapter, the temp stayed
under 150 and everything looked o.k. to take the boat out for a run on
the 4th with the family. On the lake everything seemed o.k. with power
other than when we were pulling a tube, the power seemed a little off
gunning it out of the hole. Two days later I took it out again and
this time the power was way off. The boat , a 23 foot larson 220,
won't even get on plane. It seems to miss but all of the plugs are
firing when I did a spark test. At idle it seems fine but the engine
still seems to run like its missing a bit. I'm about to check the
timing next. The Oil pressure and temperature and normal. I did have
about 5 to 10 gallons of 10 month old gas in the tank before I filled
it up with 89 octane at the pump. I checked the oil and it looked o.k.
too.

Thanks for all you help,

Tim


Tim, I can't comment on the power loss, but the water leak is quite likely the
water circulating pump. It's a weak spot on the marinized GM 5.7 of recent
vintage. I had to replace the pumps on a pair of 1999 5.7 Crusaders after only
three years. It's not an expensive problem. The pump is easily removed, and
the part itself is around $150-$200.


-- Rich Stern
www.nitroowners.com - The Nitro and Tracker Owners Web Site
www.mypontoon.com - The Pontoon Boat Web Site
www.fishingreportdatabase.com - The Fishing Report Database
www.mysporttrac.com - The Sport Trac Web Site

Can't give you a definitive answer to what you problem is but try some
injector cleaner. 10 month old gas is old. Gas will start to varnish in 3
to 4 months, the varnish deposist then cause havoc with the feul delivery
system.

Next time drain the gas, or put some stabilizer in it before leaving it for
so long. This will help.

Good luck,

Stefan


"Tim Tisdale" wrote in message
om...
I need some help on this. This year when I cranked my 94 5.7
Mercruiser, I noticed a small water leak on the front of the motor.
I'm not a mechanic but it looks like it is near the water pump. After
letting it run for a while on a water hose adapter, the temp stayed
under 150 and everything looked o.k. to take the boat out for a run on
the 4th with the family. On the lake everything seemed o.k. with power
other than when we were pulling a tube, the power seemed a little off
gunning it out of the hole. Two days later I took it out again and
this time the power was way off. The boat , a 23 foot larson 220,
won't even get on plane. It seems to miss but all of the plugs are
firing when I did a spark test. At idle it seems fine but the engine
still seems to run like its missing a bit. I'm about to check the
timing next. The Oil pressure and temperature and normal. I did have
about 5 to 10 gallons of 10 month old gas in the tank before I filled
it up with 89 octane at the pump. I checked the oil and it looked o.k.
too.

Thanks for all you help,

Tim

"JIMinMA©" wrote in message
...
Water leaking from a circ. pump can be sprayed all over the engine. Your
dist. cap is probably wet causing cross firing.


I'm just watching this conversation, but if your idea turns out to be
accurate, he oughta send you a case of wine.

Buy a compression guage kit at any auto parts store for around $20.00 or so.
You remove the spark plugs and install the fitting into the plug hole.
Crank the engine over (remove kill switch so it won't crank) and read the
guage. All cylinders should be within 10 lbs of each other (5 is better).
If a cylinder is low - depends on why. Rings - expensive. Head/valves -
not too bad.


Tony

"Tim Tisdale" wrote in message
om...
I really want to thank everybody who responded to this problem. You
guys are good people. To answer a couple of questions, I really didn't
find any water on the back of the engine when I removed the cover. It
seems when the engine is running at higher RPMs, the leak is hardly
there if at all. It seems to leak the most at idle. I checked the
timing and it's at 8 BTDC. Does fuel add to the carbs 1 jet at a time
as you increase RPMs? I noticed that the left jet on the 4 barrel is
putting out more gas than the right jet but that was only running at
around 1200 RPMs. If I goose the motor in Neutral, It seems to sound
o.k. but I think that's probably not an accurate test. What kind of
tool do I need to do a compression test? If a Cylinder is low on a
compression test, does that mean big money?

Thanks guys.

TT

On 10 Jul 2003 20:09:00 -0700, (Tim Tisdale)
wrote:

Does fuel add to the carbs 1 jet at a time
as you increase RPMs? I noticed that the left jet on the 4 barrel is
putting out more gas than the right jet but that was only running at
around 1200 RPMs

Tim,

Don't know if this will help, but...

My nephew and I have the same engine in our 22 footer with a
quadra-jet carb. The nephew calls it a quarda-puke and says that they
are notouious for not opening up on all four consistantly. He's
rebuilt it but we have low rpm problems at times.

PS I tell other boaters that I have "52 feet of boat". Some (those
who know how much our boating hobby costs) look at me and think
"Here's a guy with too much money", or "Gee I wish I could afford a 52
footer."

The I hit them with: "Yep, 52 feet. Two 15's and a 22."

Q

You need a compression tester which is available at any auto parts store
or Sears. Get the type you screw into the spark plug hole, not the kind
that looks like a marital aid. Make sure to remove all the plugs before
you start and block the throttle and choke wide open. If you are lucky,
you will find low compression in the cylinder near the water leak and end
up replacing a head gasket.

Tim Tisdale wrote:

I really want to thank everybody who responded to this problem. You
guys are good people. To answer a couple of questions, I really didn't
find any water on the back of the engine when I removed the cover. It
seems when the engine is running at higher RPMs, the leak is hardly
there if at all. It seems to leak the most at idle. I checked the
timing and it's at 8 BTDC. Does fuel add to the carbs 1 jet at a time
as you increase RPMs? I noticed that the left jet on the 4 barrel is
putting out more gas than the right jet but that was only running at
around 1200 RPMs. If I goose the motor in Neutral, It seems to sound
o.k. but I think that's probably not an accurate test. What kind of
tool do I need to do a compression test? If a Cylinder is low on a
compression test, does that mean big money?

Thanks guys.

TT