pull away problems when warm
 

I have a 200hp Suzuki O/B with 3 Mikuni carburettors; all was well
until a recent service.
Now o/b starts perfectly and first run will go superb, when we stop to
change over skier/driver, typically 5 min or so stop, that is when
problem occurs.
The motor restarts OK, but when you engage gear still OK, but as you
open throttle the engine does not pick up, and usually stalls.

The simplest way is to recover seems to be:
a) engage gear and idle away at low speed for a minute or so, engine
then gets to a point where it sounds less lumpy, and it will then run
OK .... A quick 30sec run around and it will be OK to then return to
skier and do an immediate deep water start with no problems. (i.e. no
powering off engine)
b) start engine, and use fast idle lever to increase idle speed to
about 3.5 to 4k revs, do this for about 20 secs ... and again it will
clear and run OK.

This seems to me be something like choking up due to mixture incorrect
..... But why would the first run go so well?

Anybody any ideas? .... I will be taking it back to service agent, but
be good to have some ideas.


Rick

I'd be checking for air in the lines somewhere...

"tafflad" wrote in message
oups.com...
I have a 200hp Suzuki O/B with 3 Mikuni carburettors; all was well
until a recent service.
Now o/b starts perfectly and first run will go superb, when we stop to
change over skier/driver, typically 5 min or so stop, that is when
problem occurs.
The motor restarts OK, but when you engage gear still OK, but as you
open throttle the engine does not pick up, and usually stalls.

The simplest way is to recover seems to be:
a) engage gear and idle away at low speed for a minute or so, engine
then gets to a point where it sounds less lumpy, and it will then run
OK .... A quick 30sec run around and it will be OK to then return to
skier and do an immediate deep water start with no problems. (i.e. no
powering off engine)
b) start engine, and use fast idle lever to increase idle speed to
about 3.5 to 4k revs, do this for about 20 secs ... and again it will
clear and run OK.

This seems to me be something like choking up due to mixture incorrect
.... But why would the first run go so well?

Anybody any ideas? .... I will be taking it back to service agent, but
be good to have some ideas.


Rick

Sounds like a vapor lock on the fuel line.
What was the service and did they do anything to the carbs, fuel filter,
fuel line, fuel pump, etc...
Check the fuel line from tank to each carb and make sure everything is
tight.
Check the routing of the fuel line(s) and make sure nothing is laying agains
the block that would boil the fuel after setting for a minute.

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

-
"tafflad" wrote in message
oups.com...
I have a 200hp Suzuki O/B with 3 Mikuni carburettors; all was well
until a recent service.
Now o/b starts perfectly and first run will go superb, when we stop to
change over skier/driver, typically 5 min or so stop, that is when
problem occurs.
The motor restarts OK, but when you engage gear still OK, but as you
open throttle the engine does not pick up, and usually stalls.

The simplest way is to recover seems to be:
a) engage gear and idle away at low speed for a minute or so, engine
then gets to a point where it sounds less lumpy, and it will then run
OK .... A quick 30sec run around and it will be OK to then return to
skier and do an immediate deep water start with no problems. (i.e. no
powering off engine)
b) start engine, and use fast idle lever to increase idle speed to
about 3.5 to 4k revs, do this for about 20 secs ... and again it will
clear and run OK.

This seems to me be something like choking up due to mixture incorrect
.... But why would the first run go so well?

Anybody any ideas? .... I will be taking it back to service agent, but
be good to have some ideas.


Rick

Back in my old dirt bike days on the single cyl two strokes, these symptoms,
came from what we called "loaded up". After running it hard, and then
stopping, the temp would rise and the air going into the carb got very hot
(and thin) which resulted in a "rich" mixture. Several things can
contribute to the heat, such as higher heat range plugs, air intake
restriction, change to a hotter thermostat, or restriction in the cooling
system.
LD

"tafflad" wrote in message
oups.com...
I have a 200hp Suzuki O/B with 3 Mikuni carburettors; all was well
until a recent service.
Now o/b starts perfectly and first run will go superb, when we stop to
change over skier/driver, typically 5 min or so stop, that is when
problem occurs.
The motor restarts OK, but when you engage gear still OK, but as you
open throttle the engine does not pick up, and usually stalls.

The simplest way is to recover seems to be:
a) engage gear and idle away at low speed for a minute or so, engine
then gets to a point where it sounds less lumpy, and it will then run
OK .... A quick 30sec run around and it will be OK to then return to
skier and do an immediate deep water start with no problems. (i.e. no
powering off engine)
b) start engine, and use fast idle lever to increase idle speed to
about 3.5 to 4k revs, do this for about 20 secs ... and again it will
clear and run OK.

This seems to me be something like choking up due to mixture incorrect
.... But why would the first run go so well?

Anybody any ideas? .... I will be taking it back to service agent, but
be good to have some ideas.


Rick

Would these be where the cooling system flush would fit in?


"LD" wrote in message
...
Back in my old dirt bike days on the single cyl two strokes, these
symptoms,
came from what we called "loaded up". After running it hard, and then
stopping, the temp would rise and the air going into the carb got very hot
(and thin) which resulted in a "rich" mixture. Several things can
contribute to the heat, such as higher heat range plugs, air intake
restriction, change to a hotter thermostat, or restriction in the cooling
system.
LD

"tafflad" wrote in message
oups.com...
I have a 200hp Suzuki O/B with 3 Mikuni carburettors; all was well
until a recent service.
Now o/b starts perfectly and first run will go superb, when we stop to
change over skier/driver, typically 5 min or so stop, that is when
problem occurs.
The motor restarts OK, but when you engage gear still OK, but as you
open throttle the engine does not pick up, and usually stalls.

The simplest way is to recover seems to be:
a) engage gear and idle away at low speed for a minute or so, engine
then gets to a point where it sounds less lumpy, and it will then run
OK .... A quick 30sec run around and it will be OK to then return to
skier and do an immediate deep water start with no problems. (i.e. no
powering off engine)
b) start engine, and use fast idle lever to increase idle speed to
about 3.5 to 4k revs, do this for about 20 secs ... and again it will
clear and run OK.

This seems to me be something like choking up due to mixture incorrect
.... But why would the first run go so well?

Anybody any ideas? .... I will be taking it back to service agent, but
be good to have some ideas.


Rick

I have a 200 Metrc, thermostat is in top of the starboard head with external
line coming out to eventually go down to the "tell tale". Although I
mentioned the thermostat, it's unlikely the service shop changed it as prev.
maint. I would think you have an itemized receipt with all parts charged
for?
LD
"Chris" wrote in message
.. .
Would these be where the cooling system flush would fit in?

Sorry; Make that a Merc, not a "Metrc"
LD

"LD" wrote in message
...
I have a 200 Metrc, thermostat is in top of the starboard head with
external
line coming out to eventually go down to the "tell tale". Although I
mentioned the thermostat, it's unlikely the service shop changed it as
prev.
maint. I would think you have an itemized receipt with all parts charged
for?
LD
"Chris" wrote in message
.. .
Would these be where the cooling system flush would fit in?