Stromberg CDSE start valve and adjustment

[xebec]

I have come to the end of a restoration of my 1971 GT6 Mk3 and have now started to tune the car before getting it registered etc.

A few months ago I carried out an overhaul of the carbs to include seals, gaskets, jets etc and have come across a problem that I am unable to figure out at this time. When I pull the choke fully out the starting valve leaks underneath.  The car starts okay but I am having problems with getting it to run on the choke and consequently idle properly. The valves have been adjusted and the timing has been set to 7 deg BTDC. I managed to do this with some difficulty after messing around with the throttle screws. I managed to get it to around 900 rpm albeit really lumpy. I still need to set the mixture but would like to sort out this leak from the start valve before moving forward. Anybody any idea what the problem may be? Is there also a setting for the bolt that controls the throttle opening when pulling the choke out. I cannot find any information on buckeyetriumph.org or anywhere regarding this type of problem. Any info gratefully received. Regards, Ken

[Pete Lewis]

Its unusual for the valve to leak, are you sure its not from the float gasket, there are many versions of

gasket over the years all look similar some will not follow the casting profile and leave leaky gaps on a corner

 

Start valve discs can get corroded can be refaced on a glass block and some fine wet dry

 

if you have fitted throttle spindles as part of thr rework do you have the throttle plates the right way round

when closed there should be no daylight aroind the edges

 

set the choke fast idle to around a 1mm must have a gap but need be fast enough to keep a smooth fast idle without it hunting. Say 1500rpm on choke.

 

The feed is from a tube next to the base jet , ifnthe float is giving too high fuel level this can affect the choke

 

make sure the floats are the right way up flat top contoured bottom

the float will sit at an angle to the fuel if there are two float valve arms its easy to fit it upsidedown

[xebec]

Its unusual for the valve to leak, are you sure its not from the float gasket, there are many versions of

gasket over the years all look similar some will not follow the casting profile and leave leaky gaps on a corner

 

Start valve discs can get corroded can be refaced on a glass block and some fine wet dry

 

if you have fitted throttle spindles as part of thr rework do you have the throttle plates the right way round

when closed there should be no daylight aroind the edges

 

set the choke fast idle to around a 1mm must have a gap but need be fast enough to keep a smooth fast idle without it hunting. Say 1500rpm on choke.

 

The feed is from a tube next to the base jet , ifnthe float is giving too high fuel level this can affect the choke

 

make sure the floats are the right way up flat top contoured bottom

the float will sit at an angle to the fuel if there are two float valve arms its easy to fit it upsidedown

Hi Pete,

Thanks for the info. I have checked everything and all appears okay but for some reason that valve leaks. Perhaps you can see in the pics that the gasket is wet around the valve itself. I assume that a gasket is supposed to be fitted as just looking at the burlen site my carb 3335R does not show one for the valve...hmm. I initially had trouble with the carbs overflowing but found that the floats were not set properly. I have made sure they are fitted the right way up and set them to 16-17mm.  That problem disappeared however the valve leak remains. i think I am going to have to take it apart and see if I can figure out what is causing it. Thanks for your help.

[dougbgt6]

There should be a gasket. I'm surprised you couldn't find anything on buckeye, in part 2 of their carb rebuild there is a very detailed description of the valve.

 

http://www.buckeyetriumphs.org/technical/Carbs/CarbsII/CarbsII.htm

[Simon]

Have a look at the diagrams on burlen.co.uk site, if its missing contact the supplier and et them to send you one.

[xebec]

Have a look at the diagrams on burlen.co.uk site, if its missing contact the supplier and et them to send you one.

The diagram for my carbs 3335L/R on the burlen site does not show a gasket for the cold start device and therefore I am thinking it maybe should not have one. The buckeye site shows the device but does say a gasket should be fitted but I cannot find a pattern for this at all. A couple of sites say that no gasket is used. I am confused now. I am going to remove the device and see what's what....

[Simon]

Maybe give them a call.

[Waynebaby]

Ken,

 

I also have a leak from the CDSE starter valve which I can't seem to fix, but other than a slight dampness with petrol around the rear of the front carb the leak does not cause me any problems with running. This isn't going to help you much, but it could be that your idling problem relates to something other than the starter valve. When I first got my GT6 Mk3 it idled very badly and that turned out to be because the previous owner had installed the cover on the front carb (and consequently the air valve) 90 degrees out. It would be worth double checking that the words CD STROMBERG on both covers are pointing towards the front of the car to eliminate this as a cause of the poor idling.

 

I have copied the instructions for setting the fast idle given in the owners handbook below. I hope this helps:

 

Check that the choke lever and cam is against its stop (the piece of square section metal beneath the starter valve) when the choke control knob is pushed fully home. If necessary re-adjust the cable to achieve this condition.

 

Pull the choke knob out sufficiently to bring the cable trunnion into alignment with the centre of the fast idle adjusting screw and the centre of the starter valve. Slacken the locknut and unscrew the fast idle screw until it is touching the cam on the starter valve actuator.

 

Start the engine and while it is cold (68 to 86 degrees F) adjust the fast idle screw to give a tacho reading of 1100 rpm. Tighten the locknuts, re-check the fast idle speed and when satisfactory, push the choke knob fully home and stop the engine.

 

Wayne

[dougbgt6]

This is a picture of a Rimmer gasket set, I think the grey one on the left is the one?

 

 

http://www.rimmerbros.co.uk/Item--i-516990

[dougbgt6]

No sorry wrong again! That's the bypass valve gasket  But I'm sure my repair kit came with a cold start gasket.

[Paul H]

Hi - im late to this thread and have a limited knowledge on carbs BUT I do have a pair of refurb cdse carbs ( prepared by Turner Carbs) on my vitesse Mk2  - Can I assist in this gasket issue if so point me in the right direction 

 

Paul 

[xebec]

Thanks all for your amazing input. I have attached a few pics so you can see where I am at the moment.

The CD Stromberg text on my carbs is pointing toward the engine so I will change them to point towards the front of the engine.

Thanks for the info regarding the setting up of the fast idle as that is very useful.

I have detached the cold start device from the carb and have found a gasket (see pic) although not the best fit is fitted to the rear part of the device. This was the part that was leaking as the gasket was wet.

I am wondering if this is the correct gasket. There was no gasket between the front part which I assume is correct. I assume the device is put together properly and the holes are in the correct place.

Thanks again all.

[Pete Lewis]

think you need 517859    canley sell them as seperates

 

very few places show the siamese fuel outlet hsg for the rear carb   what a surprise   think you will need a gasket either side of this 

 

 

check the faces have no bruised or burrs to upset the mating faces 

[Waynebaby]

Hi Ken,

 

That gasket looks the same as mine did and as far as I am aware there is only one in the cold start device. I've done a bit more reading and another way to set the fast idle is to adjust the fast idle adjustment screw so that there is 0.8mm gap between the screw head and the cold start cam when the choke knob is fully home. 

 

Good luck

 

Wayne

[dougbgt6]

Actually that IS the gasket I pointed out! So, not so  after all. Time for my medication.

[xebec]

Hi Ken,

 

That gasket looks the same as mine did and as far as I am aware there is only one in the cold start device. I've done a bit more reading and another way to set the fast idle is to adjust the fast idle adjustment screw so that there is 0.8mm gap between the screw head and the cold start cam when the choke knob is fully home. 

 

Good luck

 

Wayne

Hi Wayne,

Thanks for that, so I now know that what I have is correct, brilliant. I have changed the top covers so that the text points to the front of the engine. I am going to put it all back together, adjust as necessary and see how things pan out. cheers all....Ken

[Pete Lewis]

Both sides of the chamber ( with the two poppet valves) which supplies the rear carb will need a gasket

 

knowone shows this little darling, most only show the single choke set up .

 

the outer with the conrol shaft does not have one

 

I will get me coat and Dougs meds may be useful

 

pete

 

 

 

 

pete

[xebec]

Well I thought I was getting on so well however, today i bolted on the airfilters pulled out the choke and tried to start her. She fired up and ran really lumpy. When checking the carbs petrol was pouring out the bottom in the area of the intakes. It was dripping out pretty fast and the gaskets on the float bowls were wet. She eventually died on me and when checking the plugs they are really black. To be expected. I cannot adjust the mixture as I have not got that far as the other problems keep getting in the way. I cannot understand what is going wrong here as the floats are set at 16-17mm, the jets are working okay and moving easily and I have a low pressure Hardi electric fuel pump giving out 2.1 psi.

Any ideas what I am doing wrong here please as i am at a loss as to how to proceed. Please see pics of float chambers etc.

[Pete Lewis]

now from my days with these i would have said float upside down,  trouble with that is places like excellent buckeye triumphs shows as you have

browsing some manuals and it gets more cloudy , some show flat face in fuel others show contoured face in fuel  !!!!!!!!!!!!!!

 

which ever if its squirting fuel from the front face vent then the level is far too high   

which is back to valve not seating  ...debris inside or worn out

too much fuel pressure ...yours sounds Ok 

 

theres no other  contenders  for flooding  from the breather port .  

 

but is this from the breather port or  is fuel welling out of the jet  ?????

 

make sure its not the chamber gasket is wrong contour  these have small evolution  changes and can leave corners not sealed 

then thats fuel out from under side not cleaner side... just needs a careful look

 

Pete

[Waynebaby]

Ken,

 

Fuel dripping out of the intake area along with lumpy running sounds like it might be the flooding due to the float needle valves not seating properly - often because of minute shavings of rubber fuel hose getting trapped in the valve seat. I'd suggest that you take out the float needle valves, visually check them and the hole they screw into for black particulate and give them a blow through. I have this problem whenever I disturb the fuel pipes connected to the carbs and it often takes a couple of attempts before I get rid of all the offending material.

 

Wayne

[Pete Lewis]

this is a old nutshell , its a good reason to reduce the number of connections to a minimum and dump some of the metal .

 

we had this on introducing nylon air brake pipes back in the 70s   

 

be they plastic or rubber slivers the little sods get cut off when you insert the bundy into the hose and float to where you get grief

 

                                and they hide !!!

 

always a good idea  get a good squirt from the pipes into a jar before connecting to to carbs  and then you make some more   .....

 

Pete

[xebec]

Today I have checked the carb valves, float etc and have cleaned everything again with carb cleaner. I have also taken the starter valve apart again and flushed that out with carb cleaner. I have also adjusted the needle setting as I saw a reference to it on buckeye that for a starting position the needle should be one complete turn anticlockwise after winding it up to the fully clockwise position. I have the adjuster tool to adjust the carb mixture from above.

I reassembled everything and fitted them to the car. I then started the car on the choke and lo and behold it started fine (always did) however this time no leaks (hooray).....

This was without the air cleaner on and hopefully with them on ( I am awaiting some K&N's tomorrow) it will still behave itself. Whether the solution was the position of the needle or the cleaning I have no idea but it is as of this moment leak free. My colortune shows a nice bluey/yellowish colour and this without having to do more adjustment. Timing is at 7 deg BTDC.

I assume the fitting of the air cleaners should not make too much difference, hopefully not anyway. Thanks for all the inputs. Regards, Ken

[Pete Lewis]

it wont be the needle  they  dont cause flooding ,  its fuel levels , or blocked breathers

 

what ever you fit do make sure the filter box  does not obstruct any of the front face vent holes 

 

as for fitting KN you have likely just started a debate on now there's free flowing air you have lost the intake vacuum and a good chance you will need a richer needle, which wont be available for strombergs as they are very limited in thier availability

 

so be prepared for more strong tea and much twiddling,  the std needles will get youa idle mixture but are going to be too weak up the range 

 

fitting a stronger damper spring or damper weight  may give you a compromise

 

lets see how you get on 

 

keep at it 

 

Pete

[xebec]

Well this is turning into a bit of a nightmare. This morning went out to fit the K&N's on the GT6 and although at first I did not take very much notice of the situation with the carbs I noticed that the front carb float cover gasket was wet. There was no petrol in the carb throat however I went ahead and assembled the air filters. I decided to start the car and after pulling out the choke and cranking it over the car started albeit not willing to run on the choke very well. I attempted to get it to run properly however I again noticed petrol dripping out of the carb throats and coming out the bottom of the filters. Please see pic of front carb, also noticed later that the rear one was exactly the same. I assume this was coming from the front carb via the starter valve assembly. I can only imagine that the valve when left overnight does not seal properly as when I remove it and fiddle around with it it works okay and then when reassembled it works for a while and then decides to act up when it is static. I have just ordered some new valves, floats and gasket set for my carbs 3335's from Burlen. I am starting to pull my hair out here.

[Pete Lewis]

To get fuel on the bridge you have either too much fuel level, be that pump pressure , failed float needle or float heights, but.......the fuel is not from the choke side this is up thro the jet or you have some serious

leaks or missfitting sealing on the pressed in base jet assy

 

If you pull, out the piston the fuel should be just visible a few mm below the top of the jet bush

if its perculating out , its too high dry it all with piston out and leave overnight again. See exactly where its eminating from

 

these should not be this troublesome

 

pete

 

 

 

I would also double check your pump pressure