About that ball/spring thing ... it's function is still not clear to me, but
.... it's purpose seems to be to balance the cold water bypass to the 2 sides
of the (e.g. my V6) engine. There's a pic of it ... it's at the top of the
lower (bottom) diagram ... Warm Manifold System. So if one manifold is cold,
maybe the thermostat is not opening as soon as it should (engine is actually
overheating) and cold water is being directed more to one manifold (by the
tee valve assembly) rather than to both?

The link ...
http://www.perfprotech.com/home/tech...oling-tips.htm

Hey, just thinking out loud here :-)

In my V6, there's a ball/spring mechanism in the cooling system that I
come
across every fall when I pull all the water lines for draining/winter
storeage. I've just now looked through my Seloc manual, and don't see it.
It
may have something to do with controlling water flow to each manifold ...

I had a little look at that link and am having trouble following the
description - not the type of thing to read in a quick scan!

In the meantime, the engine is still intermittently running rough (when run
at low speed on hot days for 20-30 minutes, clears up in a few minutes under
higher load...). I have found corrosion inside the distributor cap and will
be replacing that, then reassessing - the number of possible causes that I
have come up with is a little staggering - and my mechanic agrees!

I also favour having a look inside the carburetor, but mechanic is hesitant,
saying they're often never the same after, in his experience ... hmm...

====

Charles T. Low
www.boatdocking.com

====

"Bowgus" wrote in message
...
About that ball/spring thing ... it's function is still not clear to me,
but
... it's purpose seems to be to balance the cold water bypass to the 2
sides
of the (e.g. my V6) engine. There's a pic of it ... it's at the top of the
lower (bottom) diagram ... Warm Manifold System. So if one manifold is
cold,
maybe the thermostat is not opening as soon as it should (engine is
actually
overheating) and cold water is being directed more to one manifold (by the
tee valve assembly) rather than to both?

The link ...
http://www.perfprotech.com/home/tech...oling-tips.htm

Hey, just thinking out loud here :-)

Charles T. Low wrote:
I had a little look at that link and am having trouble following the
description - not the type of thing to read in a quick scan!

In the meantime, the engine is still intermittently running rough (when run
at low speed on hot days for 20-30 minutes, clears up in a few minutes under
higher load...). I have found corrosion inside the distributor cap and will
be replacing that, then reassessing - the number of possible causes that I
have come up with is a little staggering - and my mechanic agrees!

I also favour having a look inside the carburetor, but mechanic is hesitant,
saying they're often never the same after, in his experience ... hmm...

====

Charles T. Low
www.boatdocking.com


One should expect it to be somewhat better, and in no qualified
hands, ever the worse for care.

My old zenith carb was worn so bad that the throttle shaft rattled
on idle, its' fibre end washers worn way out, delivering varying
amounts of vacuum leak into the intake manifold, which really made
life with the old girl an erratic thing, to say the least,
particularly when lower power settings were needed. As well, a
somewhat sticky needle valve must have been able to stick either
open or closed, mysteriously and capreciously. It's better, now.

Fixing a carburettor is an essential basic automotive and boating
skill which, thanks to induction fuel injection and computerised
engine control, is becoming a skill of the past. If your mech is
dubious, you need a real mech.

A couple of small rubber "O" rings on the ends of the shaft,
retained with a little brass snare wire seems to have steadied the
engine up considerable.

Trry K


====

"Bowgus" wrote in message
...

About that ball/spring thing ... it's function is still not clear to me,
but
... it's purpose seems to be to balance the cold water bypass to the 2
sides
of the (e.g. my V6) engine. There's a pic of it ... it's at the top of the
lower (bottom) diagram ... Warm Manifold System. So if one manifold is
cold,
maybe the thermostat is not opening as soon as it should (engine is
actually
overheating) and cold water is being directed more to one manifold (by the
tee valve assembly) rather than to both?

The link ...
http://www.perfprotech.com/home/tech...oling-tips.htm

Hey, just thinking out loud here :-)

Thanks, Terry,

A marine mechanic to me is a bit like a hairdresser to my wife - we have a
relationship, and I feel loyal. That might interfere with getting my carb
maintained, however, and I'll have to think about how to approach that. I'll
come up with something. Step number one will be to replace my distributor
cap, rotor and leads (they have to be specially ordered - old engine,
1978...) and then reassess.

====

Charles T. Low
www.boatdocking.com

====

"Terry Spragg" wrote in message
...
One should expect it to be somewhat better, and in no qualified hands,
ever the worse for care.

My old zenith carb was worn so bad that the throttle shaft rattled on
idle, its' fibre end washers worn way out, delivering varying amounts of
vacuum leak into the intake manifold, which really made life with the old
girl an erratic thing, to say the least, particularly when lower power
settings were needed. As well, a somewhat sticky needle valve must have
been able to stick either open or closed, mysteriously and capreciously.
It's better, now.

Fixing a carburettor is an essential basic automotive and boating skill
which, thanks to induction fuel injection and computerised engine control,
is becoming a skill of the past. If your mech is dubious, you need a real
mech.

A couple of small rubber "O" rings on the ends of the shaft, retained with
a little brass snare wire seems to have steadied the engine up
considerable.

Trry K

Hi Charles,
I once owned a 1977 GMC van with a 350 carbureted engine. I bought it (ab)used and it used 1 quart of oil for 500 miles,
I started using 20W-50 oil as the back plugs would foul with oil in the course of about 5000 miles, and I would have to
pull them and clean them. It also would run rough if it was idled too much and would clear up once out on the highway.
I pulled the valve covers and found oil sitting there. The problem was the oil drain holes in the head were plugged and
the oil was going down the valve stems into the piston chambers. I plunged out the holes with a coat hanger and the
entire problem went away. I then got over 2000 miles to a quart of 10W-30 and the plugs never fouled again.
On this same vehicle I installed a GM professionally rebuilt carburetor and then immediately had to have it
repaired/rebuilt by a local small engine place, who put the proper Power valve spring in.
FWIW.
Kevin

Charles T. Low wrote:
Thanks, Terry,

A marine mechanic to me is a bit like a hairdresser to my wife - we have a
relationship, and I feel loyal. That might interfere with getting my carb
maintained, however, and I'll have to think about how to approach that. I'll
come up with something. Step number one will be to replace my distributor
cap, rotor and leads (they have to be specially ordered - old engine,
1978...) and then reassess.

====

Charles T. Low
www.boatdocking.com

====

"Terry Spragg" wrote in message
...

One should expect it to be somewhat better, and in no qualified hands,
ever the worse for care.

My old zenith carb was worn so bad that the throttle shaft rattled on
idle, its' fibre end washers worn way out, delivering varying amounts of
vacuum leak into the intake manifold, which really made life with the old
girl an erratic thing, to say the least, particularly when lower power
settings were needed. As well, a somewhat sticky needle valve must have
been able to stick either open or closed, mysteriously and capreciously.
It's better, now.

Fixing a carburettor is an essential basic automotive and boating skill
which, thanks to induction fuel injection and computerised engine control,
is becoming a skill of the past. If your mech is dubious, you need a real
mech.

A couple of small rubber "O" rings on the ends of the shaft, retained with
a little brass snare wire seems to have steadied the engine up
considerable.

Trry K

Thanks, Kevin,

I'm considering having the carb rebuilt, but have been warned that sometimes
it ends up worse, even in experienced hands - or that such bad damage is
found inside that it can't be salvaged.

Something like what you're suggesting makes sense ... I just have never
personally looked into the guts of an engine enough to know quite exactly
what you mean. But is the kind of thing you're suggesting something for
mechanic, or could anybody do it? It seems to me that unbolting the covers
and having a look wouldn't be beyond the average person's capability. Then
you would need a gasket kit to put it all back together?

Charles

====

Charles T. Low
www.boatdocking.com

====

"Kevin & Debbie" wrote in message
...
Hi Charles,
I once owned a 1977 GMC van with a 350 carbureted engine. I bought it
(ab)used and it used 1 quart of oil for 500 miles, I started using 20W-50
oil as the back plugs would foul with oil in the course of about 5000
miles, and I would have to pull them and clean them. It also would run
rough if it was idled too much and would clear up once out on the highway.
I pulled the valve covers and found oil sitting there. The problem was the
oil drain holes in the head were plugged and the oil was going down the
valve stems into the piston chambers. I plunged out the holes with a coat
hanger and the entire problem went away. I then got over 2000 miles to a
quart of 10W-30 and the plugs never fouled again.
On this same vehicle I installed a GM professionally rebuilt carburetor
and then immediately had to have it repaired/rebuilt by a local small
engine place, who put the proper Power valve spring in.
FWIW.
Kevin

Hi Charles
The actual R & R of the valve covers was easy enough and the cleaning of the drain holes was a no brainer, but to get at
the covers to take them off my boat engines would be a rather large undertaking. The van engine wasn't too bad. I have
no idea if you can still buy brand new carburetors or not, it may be an option. I had considered buying a brand new
Holley back in 1980 but decided to go with the "Factory Fresh GM Rebuilt", which was junk. Apparently the most
noticeable symptom of plugged drain holes was the puff of blue smoke that would come out of the exhaust pipe when I
started the Van after it had sat for a while. I don't think I could see that on my I/O's but you might on your inboard.
Just guessing.
I would mention my experience to your mechanic to get his opinion.
Good luck and have a great long weekend.
Kevin

Charles T. Low wrote:
Thanks, Kevin,

I'm considering having the carb rebuilt, but have been warned that sometimes
it ends up worse, even in experienced hands - or that such bad damage is
found inside that it can't be salvaged.

Something like what you're suggesting makes sense ... I just have never
personally looked into the guts of an engine enough to know quite exactly
what you mean. But is the kind of thing you're suggesting something for
mechanic, or could anybody do it? It seems to me that unbolting the covers
and having a look wouldn't be beyond the average person's capability. Then
you would need a gasket kit to put it all back together?

Charles

====

Charles T. Low
www.boatdocking.com

====

"Kevin & Debbie" wrote in message
...

Hi Charles,
I once owned a 1977 GMC van with a 350 carbureted engine. I bought it
(ab)used and it used 1 quart of oil for 500 miles, I started using 20W-50
oil as the back plugs would foul with oil in the course of about 5000
miles, and I would have to pull them and clean them. It also would run
rough if it was idled too much and would clear up once out on the highway.
I pulled the valve covers and found oil sitting there. The problem was the
oil drain holes in the head were plugged and the oil was going down the
valve stems into the piston chambers. I plunged out the holes with a coat
hanger and the entire problem went away. I then got over 2000 miles to a
quart of 10W-30 and the plugs never fouled again.
On this same vehicle I installed a GM professionally rebuilt carburetor
and then immediately had to have it repaired/rebuilt by a local small
engine place, who put the proper Power valve spring in.
FWIW.
Kevin

Thanks, Kevin,

I am certainly saving this information for future use.

In the meantime, however, I discussed rebuilding the carburetor with an
engine rebuilder, and he interrogated me at length about my problem and
found it very puzzling. He did say, however, that a simple explanation could
be the richness or idle adjustment screws on the carb being out of whack (I
having been advised elsewhere "not to go near that carb!"). I backed these
two screws out a bit more (double-barreled carb) and the thing _seems_ to be
working normally again!

There's also an idle-adjustment screw on the actual shift-cable linkage, but
I'm talking about a spring-screw(s) lower down on the carburetor itself.

If it continues along like this, I'll perhaps still have the carb looked at
over the winter, but for the moment I don't want to tamper with success.

Wish me luck!

Charles

====

Charles T. Low
www.boatdocking.com

====

"Kevin & Debbie" wrote in message
...
Hi Charles
The actual R & R of the valve covers was easy enough and the cleaning of
the drain holes was a no brainer, but to get at the covers to take them
off my boat engines would be a rather large undertaking. The van engine
wasn't too bad. I have no idea if you can still buy brand new carburetors
or not, it may be an option. I had considered buying a brand new Holley
back in 1980 but decided to go with the "Factory Fresh GM Rebuilt", which
was junk. Apparently the most noticeable symptom of plugged drain holes
was the puff of blue smoke that would come out of the exhaust pipe when I
started the Van after it had sat for a while. I don't think I could see
that on my I/O's but you might on your inboard. Just guessing.
I would mention my experience to your mechanic to get his opinion.
Good luck and have a great long weekend.
Kevin