Warm engine stalls at idle. -LONG
 

This is for any of you with the "Know". A month ago, I purchased a
bass boat with a Mercury Force 70 hp motor with approximately 30 hours
of run time. I was told by the original owner that the gas was at
least a year and a half old. I took my new (used) boat to the lake
and launched it. After squeezing the bulb a few times the motor
started perfectly. I left the launch dock and proceeded to put it
through its paces. The boat and motor functioned perfectly...even the
trolling motor (but that's another story). My wife and I spent much
of the morning turning 4000 rpm up and down the lake. In the early
afternoon, about two forty-five we headed back to the boat launch.
There was a waiting list of boats both being launched and retreaved so
I waited with the engine either at idle or in forward at low rpm for
my turn. The engine started to labor and then died and would not
re-start. I was now "dead in the water". No engine and no trolling
motor (that other story). With the 5 mph breeze, I was now drifting
towards some boats that were tied up at the dock. Their owners were
nice enough to push me away and left me drifting to some children
swimming in a small cove next to the launch. After beaching the
boat, I hiked to the launch for assistance from the life guard. A
boat was sent to tow me to the launch. After getting it home, I
posted here on Google about old gas and I subsequently siphoned out
all of the old gas; about 12 1/2 gallons. I removed, cleaned and
re-installed the three spark plugs. This past Thursday, I put 12
gallons of 89 octane into the tank and added 31 ounces of 2 stroke
oil. On Friday I attached the "ear muffs" to the engine, started the
water flowing and started the engine to let the "New" gas get to the
engine. The engine ran fine at idle as well as up to 1500 rpm, though
there seems to have been insufficient water flow because the engine
heat buzzer started. I shut down the engine and put my toys away.
This morning I took the boat back to the lake. It started without
problem. It turned 3500 - 4000 rpm with no problem. It idled (in
gear) for five minutes...No problem. On my way back to the launch
from the other side of the lake, I was in a "No Wake" area so I
started the engine and with it in gear, I proceeded toward the launch
turning about 750 -1000 rpm. Within five minutes it labored, stalled
and would not re-start-AGAIN. A very nice fisherman, towed me back to
the launch. This time the trowling motor was functioning and I was
able to get the boat to the dock. It now sits in front of my
motorhome, next to my house.

Question: Besides buying a different motor, what do you thing could
be causing the motor to labor and stall and not re-start? I am
prepared to take it to the local boat mechanic and have them do a
tune-up.

----A tune-up. I think I'll name the boat "TUNA-P"

Please....Your thoughts and suggestions.

Thanks from the Skipper of the "Tuna-p"

Warm engine stalls at idle. -LONG
 

Sounds like the plugs are fouling from long periods of idle. My guess is
the carbs need a good cleaning (from setting for so long) and a new set of
plugs.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"Harvey Arkawy" wrote in message
om...
This is for any of you with the "Know". A month ago, I purchased a
bass boat with a Mercury Force 70 hp motor with approximately 30 hours
of run time. I was told by the original owner that the gas was at
least a year and a half old. I took my new (used) boat to the lake
and launched it. After squeezing the bulb a few times the motor
started perfectly. I left the launch dock and proceeded to put it
through its paces. The boat and motor functioned perfectly...even the
trolling motor (but that's another story). My wife and I spent much
of the morning turning 4000 rpm up and down the lake. In the early
afternoon, about two forty-five we headed back to the boat launch.
There was a waiting list of boats both being launched and retreaved so
I waited with the engine either at idle or in forward at low rpm for
my turn. The engine started to labor and then died and would not
re-start. I was now "dead in the water". No engine and no trolling
motor (that other story). With the 5 mph breeze, I was now drifting
towards some boats that were tied up at the dock. Their owners were
nice enough to push me away and left me drifting to some children
swimming in a small cove next to the launch. After beaching the
boat, I hiked to the launch for assistance from the life guard. A
boat was sent to tow me to the launch. After getting it home, I
posted here on Google about old gas and I subsequently siphoned out
all of the old gas; about 12 1/2 gallons. I removed, cleaned and
re-installed the three spark plugs. This past Thursday, I put 12
gallons of 89 octane into the tank and added 31 ounces of 2 stroke
oil. On Friday I attached the "ear muffs" to the engine, started the
water flowing and started the engine to let the "New" gas get to the
engine. The engine ran fine at idle as well as up to 1500 rpm, though
there seems to have been insufficient water flow because the engine
heat buzzer started. I shut down the engine and put my toys away.
This morning I took the boat back to the lake. It started without
problem. It turned 3500 - 4000 rpm with no problem. It idled (in
gear) for five minutes...No problem. On my way back to the launch
from the other side of the lake, I was in a "No Wake" area so I
started the engine and with it in gear, I proceeded toward the launch
turning about 750 -1000 rpm. Within five minutes it labored, stalled
and would not re-start-AGAIN. A very nice fisherman, towed me back to
the launch. This time the trowling motor was functioning and I was
able to get the boat to the dock. It now sits in front of my
motorhome, next to my house.

Question: Besides buying a different motor, what do you thing could
be causing the motor to labor and stall and not re-start? I am
prepared to take it to the local boat mechanic and have them do a
tune-up.

----A tune-up. I think I'll name the boat "TUNA-P"

Please....Your thoughts and suggestions.

Thanks from the Skipper of the "Tuna-p"

Warm engine stalls at idle. -LONG
 

Thanks, Tony. I'm planning on taking it in as soon as I can find a
boat mechanic that isn't swamped with work.


"Tony Thomas" wrote in message news:eSXOc.65994$eM2.43049@attbi_s51...
Sounds like the plugs are fouling from long periods of idle. My guess is
the carbs need a good cleaning (from setting for so long) and a new set of
plugs.

--
Tony
my boats at http://t.thomas.home.mchsi.com

cut

Warm engine stalls at idle. -LONG
 

You've essentially provided all the information to solve your own problem.

I had a volvo AQ131 I/O that exhibited the same behavior. I had an
overheating problem where the engine coolant (closed system) would get up
over 210F. At lower speeds it would hover around 180F and at idle it
would get to about 190F. At idle it would run rough and would have a
tendancy to stall. When I finally fixed the cooling problem the other
problem mysteriously went away, completely!

If you are overheating at lower speeds, change the water impeller. Yes,
long periords of idle will foul the plugs, but that usually just leads to
hard starting and rough idle. What no one pointed out is sometimes
engines running hot will often vaporize the gas in the fuel bowl and cause
the engine to starve for fuel, where it runs rough, stalls, and cannot be
restarted. That is vapor lock.

Since temp alarm went off, you might not have had sufficient water to the
impeller and have now damaged the impeller, or the impeller was unable to
properly circulate the water. Either way, whether it solves your stalling
problem or not, change the impeller!

Bob Dimond

Warm engine stalls at idle. -LONG
 

"Harvey Arkawy" wrote in message
om...
This is for any of you with the "Know". A month ago, I purchased a
bass boat with a Mercury Force 70 hp motor with approximately 30 hours
of run time.

Is this a new motor, or an old motor that hasn't been run very much?


This past Thursday, I put 12
gallons of 89 octane into the tank and added 31 ounces of 2 stroke
oil.

You mixed the oil into the gas?

Doesn't your engine have oil injection?


what do you thing could
be causing the motor to labor and stall and not re-start? I am
prepared to take it to the local boat mechanic and have them do a
tune-up.

Sounds like a classic case of fouling plugs. It is common for two cycle
engines to get an oil buildup on the plugs which makes the engine run poorly
and hard to start.

I asked about the oil injection because if you are adding oil to the gas,
and the engine is injecting what it thinks it needs, then you will have
twice the oil and fouling is much more likely.

Another reason that the plugs could foul is that the spark is weak. A weak
spark may be okay when the plugs are new but once they get a coating of oil
on them the spark may not be strong enough to burn through the layer of oil.
You may also be running the incorrect spark plug, check the owners manual
for the proper spark plug number.

While you should certainly fix the fouling problem you might also want to be
alert to the symptoms. As soon as the engine starts to miss put it in
neutral and rev the engine up a bit.


Rod

Warm engine stalls at idle. -LONG
 

Rod,
The motor is a 1995 model. It doesn't have oil injection. The oil
goes into the gas tank. The original owner stated that the boat &
motor only had about 30 hours total and that it had been about a year
and a half since it had been in the water. Since it stalls when warm,
I'm more inclined to believe that vapor lock is causing my problem. I
will have the impeller checked out as soon as I can find a Mercury
Force mechanic who is not swamped with work.

Thanks all for your input. It is most appreciated.

Harvey
"Rod McInnis" wrote in message ...
"Harvey Arkawy" wrote in message
om...
This is for any of you with the "Know". A month ago, I purchased a
bass boat with a Mercury Force 70 hp motor with approximately 30 hours
of run time.

Is this a new motor, or an old motor that hasn't been run very much?


This past Thursday, I put 12
gallons of 89 octane into the tank and added 31 ounces of 2 stroke
oil.

You mixed the oil into the gas?

Doesn't your engine have oil injection?


what do you thing could
be causing the motor to labor and stall and not re-start? I am
prepared to take it to the local boat mechanic and have them do a
tune-up.

Sounds like a classic case of fouling plugs. It is common for two cycle
engines to get an oil buildup on the plugs which makes the engine run poorly
and hard to start.

I asked about the oil injection because if you are adding oil to the gas,
and the engine is injecting what it thinks it needs, then you will have
twice the oil and fouling is much more likely.

Another reason that the plugs could foul is that the spark is weak. A weak
spark may be okay when the plugs are new but once they get a coating of oil
on them the spark may not be strong enough to burn through the layer of oil.
You may also be running the incorrect spark plug, check the owners manual
for the proper spark plug number.

While you should certainly fix the fouling problem you might also want to be
alert to the symptoms. As soon as the engine starts to miss put it in
neutral and rev the engine up a bit.


Rod

Warm engine stalls at idle. -LONG
 

"Harvey Arkawy" wrote in message
om...

The original owner stated that the boat &
motor only had about 30 hours total and that it had been about a year
and a half since it had been in the water.

I have my own horror story about low hours Mercury outboards that sat for a
year. I hope yours turns out better than mine!

Since it stalls when warm,
I'm more inclined to believe that vapor lock is causing my problem. I

Does the motor have a squeeze bulb between the tank and the motor? If you
are experiencing a vapor lock situation then simply giving the bulb a
squeeze should clear it up. If that helps the situation then I would
recommend changing the fuel pump.

From your earlier post I had the impression that once the engine died it
wouldn't restart until you changed the plugs. This wouldn't be vapor lock.


will have the impeller checked out as soon as I can find a Mercury
Force mechanic who is not swamped with work.

Water pump impeller is not that hard to change. The lower unit bolts to the
mid section with four or five bolts. Remove the bolts and drop the lower
unit and you should have easy access to the water pump housing. 4 to 6
small screws should hold the pump housing on and the impeller is under that.
It will take you less time to change it yourself then driving the boat down
to the dealer.


Rod

Warm engine stalls at idle. -LONG
 

Rod,

Yes it has a squeeze bulb. Been there, done that; it didn't help.
When I removed the plugs after the first shut down, they looked
relatively clean. I wiped them off and re-installed them. The engine
runs fine when the outside air is cool, but in the afternoon sun, it
stumbles and stalls. The problem could be the impeller not delivering
enough water, it could be the fuel pump, at this point I'm too
embarrassed to be towed back to the dock again without at least
letting a mechanic check it out. Unfortunately I must wait until
August 21 for an appointment. Since the boat shop is near the lake,
they can take it out and hopefully the problem will be fixed or maybe
they will need to be towed.

Thanks for your input.

Harvey

"Rod McInnis" wrote in message ...
"Harvey Arkawy" wrote in message
om...

The original owner stated that the boat &
motor only had about 30 hours total and that it had been about a year
and a half since it had been in the water.

I have my own horror story about low hours Mercury outboards that sat for a
year. I hope yours turns out better than mine!

Since it stalls when warm,
I'm more inclined to believe that vapor lock is causing my problem. I

Does the motor have a squeeze bulb between the tank and the motor? If you
are experiencing a vapor lock situation then simply giving the bulb a
squeeze should clear it up. If that helps the situation then I would
recommend changing the fuel pump.

From your earlier post I had the impression that once the engine died it
wouldn't restart until you changed the plugs. This wouldn't be vapor lock.


will have the impeller checked out as soon as I can find a Mercury
Force mechanic who is not swamped with work.

Water pump impeller is not that hard to change. The lower unit bolts to the
mid section with four or five bolts. Remove the bolts and drop the lower
unit and you should have easy access to the water pump housing. 4 to 6
small screws should hold the pump housing on and the impeller is under that.
It will take you less time to change it yourself then driving the boat down
to the dealer.


Rod