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Carbs

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Re: Carbs
#31
Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Are you observing this with the engine running or stopped? Stopped the pistons should be sitting down on the bridge. They should move up and down freely.

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Re: Carbs
#32
J.P.Rap Avatar
J.P.Rap J.P. Rap
Mount Hope, Ontario, Canada   CAN
1976 Triumph 1500 "Donna"
2007 Ford Ranger
Assuming you mean with the engine off, it could be a bad (or missing) spring in the right carb or debris in the air valve.



"In this world, you must be oh so smart, or oh so pleasant. Well, for years I was smart. I recommend pleasant." Elwood P. Dowd

Re: Carbs
#33
regnaston Dale Sanger
Belle River, Ontario, Canada   CAN
1965 Triumph Spitfire "Frankenspit"
In reply to # 1497942 by J.P.Rap Assuming you mean with the engine off, it could be a bad (or missing) spring in the right carb or debris in the air valve.

It is with the engine running.. I never really looked while it was off.. I will check tomorrow

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Re: Carbs
#34
J.P.Rap Avatar
J.P.Rap J.P. Rap
Mount Hope, Ontario, Canada   CAN
1976 Triumph 1500 "Donna"
2007 Ford Ranger
The piston height is controlled by vacuum. The spring is calibrated to counteract the vacuum at a precise measure. The vacuum in the piston chamber is drawn through a non-adjustable port from the mixing chamber.
What that means is the vacuum in the piston chamber is controlled by the vacuum in the mixing chamber. The vacuum in the mixing chamber is determined by how far open the throttle is. If all the parts are working correctly then one throttle plate must be open more then the other causing a higher vacuum in that carb.
The first thing to check is that all parts are working correctly... No restrictions in the ports, pistons are moving smooth and freely, springs are intact and not deformed, Throttles are not sticking.
If all that checks out then they most likely need to be tuned. My car has one carb so I'm no help to you for tuning a pair.
HTH



"In this world, you must be oh so smart, or oh so pleasant. Well, for years I was smart. I recommend pleasant." Elwood P. Dowd

Re: Carbs
#35
regnaston Dale Sanger
Belle River, Ontario, Canada   CAN
1965 Triumph Spitfire "Frankenspit"
I think I found the problem. The oil in the Carbs was low. I refilled and the carbs look better, both at idle and while off (and when pressing the throttle )

I also did the ear test to adjust them, but also ordered a uni-syn so that I can make sure they are dialed in perfctly

Re: Carbs
#36
regnaston Dale Sanger
Belle River, Ontario, Canada   CAN
1965 Triumph Spitfire "Frankenspit"
So I bought a colortune kit. I assume the mixture screw is the same thing labeled "17 - Needle - Idle trimming adjusting" in this pdf

(Carbs are CDSE150)

http://www.marineengine.com/parts/technical_information/sierra_18-7085.pdf


If not where is it located? Also what do I turn to adjust vacuum

(yes I am a noob grinning smiley )

Re: Carbs
#37
Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Nope, read under special instructions about the idle trimming screw. After an engine is run in, most the time this screw is lightly snug in all the way. You won't notice any change with that screw.
You'll have to work with your main jet and your idle adjustment screw. Use your color tune to get an idea of where you are.

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Re: Carbs
#38
regnaston Dale Sanger
Belle River, Ontario, Canada   CAN
1965 Triumph Spitfire "Frankenspit"
In reply to # 1498497 by Bpt70gt Nope, read under special instructions about the idle trimming screw. After an engine is run in, most the time this screw is lightly snug in all the way. You won't notice any change with that screw.
You'll have to work with your main jet and your idle adjustment screw. Use your color tune to get an idea of where you are.

Can you give a brief explanation how?

I dont see "idle adjustment screw " in that diagram (unless it is labeled something else)

How do I adjust the jet?

Is adjusting the jet also adjusting vacuum? If not how do I do that?

Re: Carbs
#39
Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Should be an instruction sheet with the Colortune. Basically install the special plug and look at the color of the burn. Use the instructions and then determine if you are running rich or lean.
The idle adjustment screw just opens up the butterfly to each carb but you need to loosen the coupling between the carbs so they are independent of each other.
Depending on your carbs date of manufacture, mine are adjusted with a special tool inserted through the oil damper, you hold the tool so you don't twist the piston and then turn the hex wrench to enrichen or lean it out. You can only turn this a couple turns or you'll dis-engage the needle.
Adjusting the jet you are adjusting amount of fuel.
Adjusting the idle screw makes adjustments to the amount of air traveling over the bridge and can only do this at idle.
This all assumes your engine is capable of running and idling. There are so many other things that have to be attended to such as no vacuum leaks, the valve tappets are set good, good compression etc. etc. Are you using points or has the engine be converted to electronic ignition?
Books have been written on tuning these cars. Do you have a good service manual for the GT6? That would be a good start and good reading to better understand the basics.

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Re: Carbs
#40
Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
Most Spits come back rich so it'll be orange.

We have to lower the needle on the piston to lean it out which means turning the tool COUNTER-clockwise.


Re: Carbs
#41
regnaston Dale Sanger
Belle River, Ontario, Canada   CAN
1965 Triumph Spitfire "Frankenspit"
In reply to # 1498521 by Doug in Vegas Most Spits come back rich so it'll be orange.

We have to lower the needle on the piston to lean it out which means turning the tool COUNTER-clockwise.


so we do it through the damper then.. Will have to order one of those

Re: Carbs
#42
Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Yes, that's the right tool. Picture shows the current condition of my engine. I have had it running and she purrs like a kitten, but I've rebuilt everything so it all works as it should. Tuning an engine with other problems can be almost impossible, especially vacuum leaks.


Attachments:
P5210626.JPG    68 KB
P5210626.JPG

Re: Carbs
#43
regnaston Dale Sanger
Belle River, Ontario, Canada   CAN
1965 Triumph Spitfire "Frankenspit"
My engine seems to run pretty good right now.. just bought the uni-syn and colortune to make sure it is 100% on ... anyone have a link to that tool online?

Re: Carbs
#44
DerbyRam54 Neville Wardle
Branford, Connecticut, USA   USA
Haynes did a good book on CD carbs but it's out of print and generally lists for silly money on various used book sites. However, their "Techbook" on Webers also includes the text of the earlier book plus similar coverage of SUs and it goes for under $20:
https://www.ebay.com/i/121382991319?chn=ps&dispctrl=1

There is a chapter devoted to the CDSE carb which I think would be very helpful. Brian's suggestion of a shop manual for the GT6 is a good one, I came across this link which seems to take you to a scanned copy of sections of either the factory or the Bentley manual:
http://www.nctawebsite.com/mygarage/GT6/Group3.pdf

If you change the number (e.g, to Group6) you can get different sections. I have no idea how complete it is but it might help until you get a book of your own. It's free!

Re: Carbs
#45
Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
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