Stromberg trouble

[Webbo]

Hi , I have just serviced my cd150 which seemed to go quite well until I bolted the cover back on. This has prevented the air valve from dropping fully onto the base. Without the cover on it is fine , which seems to me to indicate a miss alignment between the cover , air valve and the needle valve, which I am sure was not there before I attempted the service. Any thoughts?

[Pete Lewis]

undo the large support  hex nut  1/2  turn

take the jet adjust nut up till the jet just touches the air piston ( Hold piston down with screwdriver down the dashpot )

give the big nut a sharptap and nip it up

 

this will centre the needle with the jet and allow it to fall with a clunck.

 

turn the jet adjuster down 3 turns 

run till hot and then adjust to give best running

 

Pte

[Webbo]

Thanks for the tip Pete will give it a go at the weekend.

[jondhm]

I hope it is not one of the later CDSE carbs, because these don't have the same means of adjusting the jet.

I would be inclined to ensure all mating surfaces are really clean - if the air valve moved OK beforehand, then it should move OK when reassembled. And then rotate the cover a few degrees either way before screwing it down to bed it in.

[Webbo]

Thanks jondhm, I don't think it is the later type but will try bedding in the cover as I have a feeling this could also be part of the problem along with the needle alignment.

[Colin Lindsay]

You have to tighten the cover screws gradually, testing for free dropping all the time. Tighten one gradually, test the drop, tighten another, keep checking for free movement and adjust as necessary until the cover is fully tightened and the piston still drops freely. You probably already know this but I’ve seen owners tighten the cover down fully with no adjustment then try to move the piston afterwards, with predictable results.

[Pete Lewis]

if you have a rubbish  thick diaphragm it wont help  

 

they should be a very light and flimsy 

 

they will  last for thousands of miles /years use

 

old wrinkled ones that  have swollen with oil can revert to normal with a quick wash in petrol

 

 

Pete

[Webbo]

Thanis again gents, I did'nt know to tighten the bolts gradually ,thinking about this seems to make sense and I suspect this could be the problem. As to the diaphragm it does seem thick, a lot thicker than the one I replaced, will try to resurrect the old one, thanks again.

[Pete Lewis]

if its made from recyled elephant condoms they tend to  be slow and the rubber holds the piston 

 

should  be flimsy,  resemble  marigold  gloves    not inner tubes 

 

Pete

[Webbo]

Pete, have just put the old flimsy diaphragm back on, sorted, happy days.

[Pete Lewis]

You See elephants have a lot to answer for

 

being a dinosaur I shouldnt comment

 

good when the basics work and ....cheap

 

 

pete