Syncing 3 carbs, How?
 

Could someone have pity on me and point me to some kind of resource
describing how to sync three carbs.

I goofed and turned the screws on my Force 85's carbs instead of the
manifold mounting screws (long story, suffice it to say I wasn't paying
attention). I heard something about listening through a hose or
something once before, but I have no idea what I'd be listening for. I'm
handy with tools and have a workshop (I live on a ranch, it's a
necessity). I've worked on pletny of things from shredders to tractors
and Jeeps and lawn mowers, but none of them have 3 carbs!

Syncing 3 carbs, How?
 

On Tue, 06 Jul 2004 09:29:52 -0500, something compelled Jeepers
, to say:

Could someone have pity on me and point me to some kind of resource
describing how to sync three carbs.

Check with one or more of the British sports car groups. They do
this all the time.

Syncing 3 carbs, How?
 

In article ,
"Steve Daniels, Seek of Spam" wrote:

On Tue, 06 Jul 2004 09:29:52 -0500, something compelled Jeepers
, to say:

Could someone have pity on me and point me to some kind of resource
describing how to sync three carbs.

Check with one or more of the British sports car groups. They do
this all the time.

Any one in particular? I'm not familiar with British technology and
would have no idea who has what.

Syncing 3 carbs, How?
 

"Steve Daniels, Seek of Spam" wrote in message

Check with one or more of the British sports car groups. They do
this all the time.

Yes. Unfortunately, most folks who've invested much time in working on a
triple rack of SU carbs are now living in "special homes", mumbling a lot,
with oatmeal dribbling down their chins. :-)

Syncing 3 carbs, How?
 

"Jeepers" wrote in message news:moomesa-

Any one in particular? I'm not familiar with British technology and
would have no idea who has what.

Do a quick google under "British sports car" or "SU carburetor".

Syncing 3 carbs, How?
 

In article ,
"John Gaquin" wrote:

SU carburetor

???

What does this mean?

Syncing 3 carbs, How?
 

Loosen all the linkage screws on the side of the carbs. With the throttle
at idle position, all the throttle plates should be down against the body.
Tighten all the linkage screws.
Now open the throttle to wide open and verify all throttle plates are
setting flat.
If one is out slightly - loosen and adjust to flat as the others.
Now back to neutral and verify all plates are the same.

Very simple on these engines.

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

"Jeepers" wrote in message
...
Could someone have pity on me and point me to some kind of resource
describing how to sync three carbs.

I goofed and turned the screws on my Force 85's carbs instead of the
manifold mounting screws (long story, suffice it to say I wasn't paying
attention). I heard something about listening through a hose or
something once before, but I have no idea what I'd be listening for. I'm
handy with tools and have a workshop (I live on a ranch, it's a
necessity). I've worked on pletny of things from shredders to tractors
and Jeeps and lawn mowers, but none of them have 3 carbs!

Syncing 3 carbs, How?
 

In article ,
Jeepers wrote:

In article ,
"John Gaquin" wrote:

SU carburetor

???

What does this mean?

Nevermind, I found it. However, I'm not too sure I have three of these.

Syncing 3 carbs, How?
 

In article rLzGc.17379$JR4.9020@attbi_s54,
"Tony Thomas" wrote:

Loosen all the linkage screws on the side of the carbs. With the throttle
at idle position, all the throttle plates should be down against the body.
Tighten all the linkage screws.
Now open the throttle to wide open and verify all throttle plates are
setting flat.
If one is out slightly - loosen and adjust to flat as the others.
Now back to neutral and verify all plates are the same.

Very simple on these engines.

Thanks! I noticed the bottom carb was not closing all the way, and I did
exactly what you suggested (it was a guess).

Somewhere I read that you could listen to the carbs through a hose. I'm
not sure why. But I tried it anyway. What I heard was the bottom one
making a more pronounced fluttering sound than the top two. What could
this be? A valve or something? Or the carb?

Would you mind helping me with another question?

I was taking the carb intake box off, while my wife was standing there
chattering at me, and therefore I stuck my screwdriver in and started
backing out the carb adjustment screws! I, apparently, thought I was
removing the airbox screws. I'm guessing these were either idle or
something else - screws. So I screwed them in gently and backed them out
2 turns, each carb. It starts and idles, but backfires and dies suddenly
if I run it up. I dunno, I goofed, and 3 carbs is a new thang fer me. I
can handle it, I just need guidance. I ordered a motor service manual
from iBoat yeaterday, but it won't arrive until the end of the week.

Syncing 3 carbs, How?
 

"Jeepers" wrote in message news:moomesa-

Nevermind, I found it. However, I'm not too sure I have three of these.

No, you probably don't. SU (Skinner Union) is a British carburetor common
on Brit sports cars of years ago, and still found in the restoration and
rally club world. Often found in tandem, banks of three, and occasionally a
double bank of three.

The point of the reference is not the carburetor itself, but the skill and
knowledge. Most of the people currently adept at tuning a bank of three
carburetors (regardless of manufacturer) will be found around the British
sports car environment, if they haven't yet gone mad.

Of course, you could also go to

http://www.iboats.com/boatproducts/m.../force_manual/

and order a manual for your engine.

JG

Syncing 3 carbs, How?
 

In article ,
"John Gaquin" wrote:

"Jeepers" wrote in message news:moomesa-

Nevermind, I found it. However, I'm not too sure I have three of these.

The point of the reference is not the carburetor itself, but the skill and
knowledge. Most of the people currently adept at tuning a bank of three
carburetors (regardless of manufacturer) will be found around the British
sports car environment, if they haven't yet gone mad.

Of course, you could also go to

http://www.iboats.com/boatproducts/m.../force_manual/

and order a manual for your engine.

JG

Love the net's timing.

Syncing 3 carbs, How?
 

Mercury vacuum gauges, as used on multi cylinder motorcycles.

Its basically 4 rod vacuum gauges affixed side by side. You attach the line
to the provided vacuum ports on the carbs (behind the throttle plates), then
while running the engine, adjust the plate(s) so that all 3 gauges read the
same.

Adjust curb idle as needed...done.

Check you local motorcycle tool shop.

--
"Do or do not...there is no try"

Yoda- 1981
"Jeepers" wrote in message
...
Could someone have pity on me and point me to some kind of resource
describing how to sync three carbs.

I goofed and turned the screws on my Force 85's carbs instead of the
manifold mounting screws (long story, suffice it to say I wasn't paying
attention). I heard something about listening through a hose or
something once before, but I have no idea what I'd be listening for. I'm
handy with tools and have a workshop (I live on a ranch, it's a
necessity). I've worked on pletny of things from shredders to tractors
and Jeeps and lawn mowers, but none of them have 3 carbs!

Syncing 3 carbs, How?
 

In article ,
"Sam S." wrote:

Mercury vacuum gauges, as used on multi cylinder motorcycles.

Its basically 4 rod vacuum gauges affixed side by side. You attach the line
to the provided vacuum ports on the carbs (behind the throttle plates), then
while running the engine, adjust the plate(s) so that all 3 gauges read the
same.

Adjust curb idle as needed...done.

Check you local motorcycle tool shop.

Sounds easy enough! Thanks!

Syncing 3 carbs, How?
 

My Mercury shop manual says you simply set them up so all the throttle plates
are seated in the idle position and that they all start to open at the same
time. That was the way the dealer mechanic did it when he set them up too. I am
not sure there is a port to vacuum test them on a Merc.

Syncing 3 carbs, How?
 

In article ,
(Greg) wrote:

My Mercury shop manual says you simply set them up so all the throttle plates
are seated in the idle position and that they all start to open at the same
time. That was the way the dealer mechanic did it when he set them up too. I
am
not sure there is a port to vacuum test them on a Merc.

Now that you mention it I'm not sure either.

What I need to know is how far the screws (near the mouth) need to be
backed out.

Syncing 3 carbs, How?
 

I seem to remember the starting point on the idle screws was 1 1/4 out, then
you adjust from there. I have been on a 60 EFI 4 stroke for 2 years now but I
had the old 3 carb 2 stroke 75 for 12 years.

Syncing 3 carbs, How?
 

In article ,
(Greg) wrote:

I seem to remember the starting point on the idle screws was 1 1/4 out, then
you adjust from there. I have been on a 60 EFI 4 stroke for 2 years now but I
had the old 3 carb 2 stroke 75 for 12 years.

So those screws on the ends of the mouths are indeed the idle screws?
There aren't any other that I can remember offhand here, away from the
motor.

Syncing 3 carbs, How?
 

The idle screws have springs on them

Syncing 3 carbs, How?
 

If you hear more air from the bottom one then sounds like it may be not set
the same as the others. Reverify it is in sync.
As for the idle screw setting - not sure on this one. I would start at
about 1 1/2 and adjust from there.
Did you accidently adjust all 3? Could you not take a reading off of one of
the other carbs?

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

"Jeepers" wrote in message
...
In article rLzGc.17379$JR4.9020@attbi_s54,
"Tony Thomas" wrote:

Loosen all the linkage screws on the side of the carbs. With the
throttle
at idle position, all the throttle plates should be down against the
body.
Tighten all the linkage screws.
Now open the throttle to wide open and verify all throttle plates are
setting flat.
If one is out slightly - loosen and adjust to flat as the others.
Now back to neutral and verify all plates are the same.

Very simple on these engines.

Thanks! I noticed the bottom carb was not closing all the way, and I did
exactly what you suggested (it was a guess).

Somewhere I read that you could listen to the carbs through a hose. I'm
not sure why. But I tried it anyway. What I heard was the bottom one
making a more pronounced fluttering sound than the top two. What could
this be? A valve or something? Or the carb?

Would you mind helping me with another question?

I was taking the carb intake box off, while my wife was standing there
chattering at me, and therefore I stuck my screwdriver in and started
backing out the carb adjustment screws! I, apparently, thought I was
removing the airbox screws. I'm guessing these were either idle or
something else - screws. So I screwed them in gently and backed them out
2 turns, each carb. It starts and idles, but backfires and dies suddenly
if I run it up. I dunno, I goofed, and 3 carbs is a new thang fer me. I
can handle it, I just need guidance. I ordered a motor service manual
from iBoat yeaterday, but it won't arrive until the end of the week.

Syncing 3 carbs, How?
 

In article 1CJGc.37696$Oq2.28736@attbi_s52,
"Tony Thomas" wrote:

If you hear more air from the bottom one then sounds like it may be not set
the same as the others. Reverify it is in sync.
As for the idle screw setting - not sure on this one. I would start at
about 1 1/2 and adjust from there.
Did you accidently adjust all 3? Could you not take a reading off of one of
the other carbs?

Yeah, I was a dumbass. My wife was distracting me and I wasn't thinking
and started backing out the screws. When I figured I had 'em out far
enough I tried to take off the airbox. Thats when I noticed the OTHER
screws on the backside of the airbox. I turned 'em in to 'stop' then
backed 'em out two full turns each. At this point I instructed my pesky
woman to go online to iBoat and order the Service Manual, which she
happily did. I await it's arrival.

The engine idles.

The bottom carb makes a fluttering sound, unlike the other two, no
matter how I adjust it. I'm afraid I'm hearing a valve or something
through the carb (and hose).


We took the 1984 Trophy out for our shakedown cruise on the Fourth.
It ran crappy at first, wouldn't get up on plane. But after a couple
minutes it suddenly "woke up" and hustled around fine. We cruised across
the lake just seeing the sights. I stopped to point out something, and
it ran crappy again after that. We limped back to the ramp and went
home. I'm assuming carb troubles because I know the boat sat for a year
before I bought it. Either that or gas vent troubles or one plug was
fouled. I dunno. I await that manual!

Syncing 3 carbs, How?
 

Tony's procedure is good. Remember, the purpose in syncing the carbs is to
have each cylinder receiving the same amount of air for a given throttle
lever position. Assuming the carbs are equally clean and that the valve
mechanism (2 stroke or 4 stroke) has the same timing per cylinder, each
cylinder should deliver the same power if the carbs are in sync. Using
vacuum gauges, etc, isn't any better than visually aligning the butterflies
looking down the throats. Usually, one carb is designated the 'reference'
carb and the others are adjusted to match that one.


"Tony Thomas" wrote in message
news:rLzGc.17379$JR4.9020@attbi_s54...
Loosen all the linkage screws on the side of the carbs. With the throttle
at idle position, all the throttle plates should be down against the body.
Tighten all the linkage screws.
Now open the throttle to wide open and verify all throttle plates are
setting flat.
If one is out slightly - loosen and adjust to flat as the others.
Now back to neutral and verify all plates are the same.

Very simple on these engines.

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

"Jeepers" wrote in message
...
Could someone have pity on me and point me to some kind of resource
describing how to sync three carbs.

I goofed and turned the screws on my Force 85's carbs instead of the
manifold mounting screws (long story, suffice it to say I wasn't paying
attention). I heard something about listening through a hose or
something once before, but I have no idea what I'd be listening for. I'm
handy with tools and have a workshop (I live on a ranch, it's a
necessity). I've worked on pletny of things from shredders to tractors
and Jeeps and lawn mowers, but none of them have 3 carbs!

Syncing 3 carbs, How?
 

In article ,
"C. J. Klingman" wrote:

Tony's procedure is good. Remember, the purpose in syncing the carbs is to
have each cylinder receiving the same amount of air for a given throttle
lever position. Assuming the carbs are equally clean and that the valve
mechanism (2 stroke or 4 stroke) has the same timing per cylinder, each
cylinder should deliver the same power if the carbs are in sync. Using
vacuum gauges, etc, isn't any better than visually aligning the butterflies
looking down the throats. Usually, one carb is designated the 'reference'
carb and the others are adjusted to match that one.

Thanks! I appreciate the info.

Syncing 3 carbs, How?
 

I would go ahead and tear down the carbs and give them a good cleaning.
There are no valves (reed valves but probably not the problem).


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

"Jeepers" wrote in message
...
In article 1CJGc.37696$Oq2.28736@attbi_s52,
"Tony Thomas" wrote:

If you hear more air from the bottom one then sounds like it may be not
set
the same as the others. Reverify it is in sync.
As for the idle screw setting - not sure on this one. I would start at
about 1 1/2 and adjust from there.
Did you accidently adjust all 3? Could you not take a reading off of
one of
the other carbs?

Yeah, I was a dumbass. My wife was distracting me and I wasn't thinking
and started backing out the screws. When I figured I had 'em out far
enough I tried to take off the airbox. Thats when I noticed the OTHER
screws on the backside of the airbox. I turned 'em in to 'stop' then
backed 'em out two full turns each. At this point I instructed my pesky
woman to go online to iBoat and order the Service Manual, which she
happily did. I await it's arrival.

The engine idles.

The bottom carb makes a fluttering sound, unlike the other two, no
matter how I adjust it. I'm afraid I'm hearing a valve or something
through the carb (and hose).


We took the 1984 Trophy out for our shakedown cruise on the Fourth.
It ran crappy at first, wouldn't get up on plane. But after a couple
minutes it suddenly "woke up" and hustled around fine. We cruised across
the lake just seeing the sights. I stopped to point out something, and
it ran crappy again after that. We limped back to the ramp and went
home. I'm assuming carb troubles because I know the boat sat for a year
before I bought it. Either that or gas vent troubles or one plug was
fouled. I dunno. I await that manual!

Syncing 3 carbs, How?
 

In article W2_Gc.41625$XM6.10685@attbi_s53,
"Tony Thomas" wrote:

I would go ahead and tear down the carbs and give them a good cleaning.
There are no valves (reed valves but probably not the problem).

Gonna do it tonight. I'll report tomorrow, unless I have trouble
installing the aerator pump.