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Default 3.0 wont idle but runs great

On Monday, July 11, 2011 at 11:02:13 AM UTC+1, Steve wrote:
Hey all, I have a 2005 3.0l mercruiser sterndrive that is acting wierd. It
will run all day long, runs great, but at the end of the day, it refuses to
idle, it just dies on me. Start it back up and it will run full throttle
just fine, but try to idle and it dies. If I let it sit for a day or two, it
goes back to running normal.
So far I have rebuilt the carb, rebuilt the fuel pump, cleaned the fuel
filter. checked for water in the gas, put another ingnition module in,
replaced the coil. Im out of things to do.
What am I missing?
Thanks
Steve



--- Posted via news://freenews.netfront.net/ - Complaints to ---


Well, sounds very similar to an issue I have at the moment.... so breaking it down
1. Forget the shutter. if it can be traced to "Only" when the engine is hot, then forget this.
2. Same with the electronic ignition components.. i.e. if it is going to fail, you will not be running at any RPM let alone high speeds.
3. Valves... here is one possibility; either adjusted too tight causing them (or at least one of them)to remain slightly open when the components are hot, then returning to running fine when cool again. Add this to cylinder head work having been done, and you have a strong possibility. Before you get all down and deep on compression analysis, try adjusting them to spec.
4. Carb, yes, possibly if you have dirt,water etc floating around in the system, but you mentioned that you had cleaned the system, and I assume you didn't just mean the carb, so unlikely.
5. Cyl head gasket, again unlikely if it is only happening while hot. One point to mention here though: if you are replacing a head gasket I recommend the use of Blue Hylomar (this will take care of any imperfections).
6. Thermostat, unlikely since you have not mentioned any association with excessive temp.
7. Impeller, again unlikely since you have not mentioned any association with excessive temp.
8. So, now to one obscure possibility, assuming all else is good..... tank vacuum; is your fuel tank breathing properly? or is it under vacuum after running a while. I only say this in case your valves are found to be fine. If the breather in your tank is blocked/restricted it will lead you to believe the issue is due to your engine being hot, when in fact it is just down to the running time (fuel consumption/hr) and nothing at all to do with temperature (Since you have not mentioned "High" temp, I am going to assume again the temp is fine). This situation will only show itself after the engine has been performing, so no use trying to sit at the jetty all day trying to troubleshoot, it Must be under load (i.e. using plenty of fuel). again like the valves, once it has been left for some time the situation returns to normal.

So, to summarise; you have 2 possibilities left:
VALVES, OR FUEL TANK.
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Default 3.0 wont idle but runs great

On 6/1/2016 11:15 AM, wrote:
On Monday, July 11, 2011 at 11:02:13 AM UTC+1, Steve wrote:
Hey all, I have a 2005 3.0l mercruiser sterndrive that is acting wierd. It
will run all day long, runs great, but at the end of the day, it refuses to
idle, it just dies on me. Start it back up and it will run full throttle
just fine, but try to idle and it dies. If I let it sit for a day or two, it
goes back to running normal.
So far I have rebuilt the carb, rebuilt the fuel pump, cleaned the fuel
filter. checked for water in the gas, put another ingnition module in,
replaced the coil. Im out of things to do.
What am I missing?
Thanks
Steve



--- Posted via
news://freenews.netfront.net/ - Complaints to ---

Well, sounds very similar to an issue I have at the moment.... so breaking it down
1. Forget the shutter. if it can be traced to "Only" when the engine is hot, then forget this.
2. Same with the electronic ignition components.. i.e. if it is going to fail, you will not be running at any RPM let alone high speeds.
3. Valves... here is one possibility; either adjusted too tight causing them (or at least one of them)to remain slightly open when the components are hot, then returning to running fine when cool again. Add this to cylinder head work having been done, and you have a strong possibility. Before you get all down and deep on compression analysis, try adjusting them to spec.
4. Carb, yes, possibly if you have dirt,water etc floating around in the system, but you mentioned that you had cleaned the system, and I assume you didn't just mean the carb, so unlikely.
5. Cyl head gasket, again unlikely if it is only happening while hot. One point to mention here though: if you are replacing a head gasket I recommend the use of Blue Hylomar (this will take care of any imperfections).
6. Thermostat, unlikely since you have not mentioned any association with excessive temp.
7. Impeller, again unlikely since you have not mentioned any association with excessive temp.
8. So, now to one obscure possibility, assuming all else is good..... tank vacuum; is your fuel tank breathing properly? or is it under vacuum after running a while. I only say this in case your valves are found to be fine. If the breather in your tank is blocked/restricted it will lead you to believe the issue is due to your engine being hot, when in fact it is just down to the running time (fuel consumption/hr) and nothing at all to do with temperature (Since you have not mentioned "High" temp, I am going to assume again the temp is fine). This situation will only show itself after the engine has been performing, so no use trying to sit at the jetty all day trying to troubleshoot, it Must be under load (i.e. using plenty of fuel). again like the valves, once it has been left for some time the situation returns to normal.

So, to summarise; you have 2 possibilities left:
VALVES, OR FUEL TANK.

Rebuild the carb again and check idle mixture. Check engine operating
temp low or high. I think you would notice a tank vacuum problem while
running under load.
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Default 3.0 wont idle but runs great

Justan Olphart wrote:
On 6/1/2016 11:15 AM, wrote:
On Monday, July 11, 2011 at 11:02:13 AM UTC+1, Steve wrote:
Hey all, I have a 2005 3.0l mercruiser sterndrive that is acting wierd. It
will run all day long, runs great, but at the end of the day, it refuses to
idle, it just dies on me. Start it back up and it will run full throttle
just fine, but try to idle and it dies. If I let it sit for a day or two, it
goes back to running normal.
So far I have rebuilt the carb, rebuilt the fuel pump, cleaned the fuel
filter. checked for water in the gas, put another ingnition module in,
replaced the coil. Im out of things to do.
What am I missing?
Thanks
Steve



--- Posted via
news://freenews.netfront.net/ - Complaints to ---

Well, sounds very similar to an issue I have at the moment.... so breaking it down
1. Forget the shutter. if it can be traced to "Only" when the engine is
hot, then forget this.
2. Same with the electronic ignition components.. i.e. if it is going
to fail, you will not be running at any RPM let alone high speeds.
3. Valves... here is one possibility; either adjusted too tight causing
them (or at least one of them)to remain slightly open when the
components are hot, then returning to running fine when cool again. Add
this to cylinder head work having been done, and you have a strong
possibility. Before you get all down and deep on compression analysis,
try adjusting them to spec.
4. Carb, yes, possibly if you have dirt,water etc floating around in the
system, but you mentioned that you had cleaned the system, and I assume
you didn't just mean the carb, so unlikely.
5. Cyl head gasket, again unlikely if it is only happening while hot.
One point to mention here though: if you are replacing a head gasket I
recommend the use of Blue Hylomar (this will take care of any imperfections).
6. Thermostat, unlikely since you have not mentioned any association with excessive temp.
7. Impeller, again unlikely since you have not mentioned any association
with excessive temp.
8. So, now to one obscure possibility, assuming all else is good.....
tank vacuum; is your fuel tank breathing properly? or is it under vacuum
after running a while. I only say this in case your valves are found to
be fine. If the breather in your tank is blocked/restricted it will lead
you to believe the issue is due to your engine being hot, when in fact
it is just down to the running time (fuel consumption/hr) and nothing at
all to do with temperature (Since you have not mentioned "High" temp, I
am going to assume again the temp is fine). This situation will only
show itself after the engine has been performing, so no use trying to
sit at the jetty all day trying to troubleshoot, it Must be under load
(i.e. using plenty of fuel). again like the valves, once it has been
left for some time the situation returns to normal.

So, to summarise; you have 2 possibilities left:
VALVES, OR FUEL TANK.

Rebuild the carb again and check idle mixture. Check engine operating
temp low or high. I think you would notice a tank vacuum problem while
running under load.


I would pull the idle jets and make sure they are clean and no detritus in
them. Depending on the carb, if the needles are a little sticky.

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Default 3.0 wont idle but runs great

On Wed, 01 Jun 2016 17:44:53 -0500, Califbill
wrote:


I would pull the idle jets and make sure they are clean and no detritus in
them. Depending on the carb, if the needles are a little sticky.


Way back in the olden days the trick was to run the idle jets in all
the way, back out them out several turns (one at a time) then rev up
the motor and cover the carb throat. The momentary high vacuum would
suck the crap out most of the time. Of course if the passages are
plugged, that may not work.
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Default 3.0 wont idle but runs great

wrote:
On Wed, 01 Jun 2016 17:44:53 -0500, Califbill
wrote:


I would pull the idle jets and make sure they are clean and no detritus in
them. Depending on the carb, if the needles are a little sticky.


Way back in the olden days the trick was to run the idle jets in all
the way, back out them out several turns (one at a time) then rev up
the motor and cover the carb throat. The momentary high vacuum would
suck the crap out most of the time. Of course if the passages are
plugged, that may not work.


My T-8 Yamaha, has such small jets that the smallest piece of junk van
screw up the low speed jet.



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Tim Tim is offline
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Default 3.0 wont idle but runs great


Anyone notice the date on this original post? "

Oh yes John. By being on google boats I always see the date and somebody probably did a search and this thread popped up. They reply to it then the thread resurfaces from the muck.

I like it. Same with Philip and his oars.

I like that one too!
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Default 3.0 wont idle but runs great

On Thu, 2 Jun 2016 07:54:32 -0700 (PDT), Tim wrote:


Anyone notice the date on this original post? "

Oh yes John. By being on google boats I always see the date and somebody probably did a search and this thread popped up. They reply to it then the thread resurfaces from the muck.

I like it. Same with Philip and his oars.

I like that one too!


Hope he posts some pics.
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Default 3.0 wont idle but runs great

On Thu, 02 Jun 2016 11:40:13 -0400, Poquito Loco
wrote:

On Thu, 2 Jun 2016 07:54:32 -0700 (PDT), Tim wrote:


Anyone notice the date on this original post? "

Oh yes John. By being on google boats I always see the date and somebody probably did a search and this thread popped up. They reply to it then the thread resurfaces from the muck.

I like it. Same with Philip and his oars.

I like that one too!


Hope he posts some pics.


Sometimes I get the idea it must be hard to start a new thread with
some of these internet portals since so many people will just start a
new question on an old thread.
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Default 3.0 wont idle but runs great

On 6/2/2016 10:54 AM, Tim wrote:

Anyone notice the date on this original post? "

Oh yes John. By being on google boats I always see the date and somebody probably did a search and this thread popped up. They reply to it then the thread resurfaces from the muck.

I like it. Same with Philip and his oars.

I like that one too!

There's a couple or three guys here who don't have both oars in the
water. Most of us know who they are. ;-)


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