Non starting herald

[iana]

First decentish day for weeks, ideal time to run the herald or so I thought. It won’t start, turns over nicely but will not run, it started and then just died. Out with the easy start and it tries to fire but will not run. Now it’s raining! I’ll swap the plugs next week and charge the battery. Any other pointers?

[iana]

It’s running points, fresh fuel, Im going to replace the plugs when it’s dry and see if that makes a difference. 

[foshi]

probably choke problem if it fires on easy start , mine took a bit of starting today needed full choke for around 10 mlnutes if tried to push in a bit would cough splutter, mind you minus 1 in farnham surrey .

[JohnD]

If it fires on "Startyabarstard" 

then you have sparks, and it's a fuel problem.

Could be needs more choke, but have a look  in the carb(s).     Crud in the float chamber?  Are the dampers moving freely?

John

[Pete Lewis]

on the downdraft its most important that when you fully pull the choke that the choke flap does fully close off the air intake throat 

when it fires there is a small spring which allows the flap to chatter  as air is drawn in ( the flap will chatter on each pistons intake 

when it fires  the flaps spring allows more air as the revs increase)

when its this cold if the choke  flap closure is restricted( partly open )   it wont start 

it might kick and die  as its not on any enriched cold starting mixture  

whip the air filter off  and look see whats going on 

[Wagger]

Your first post says first opportunity for a few weeks. Have you primed the fuel system? There may be enough fuel in the carb for it to fire, but a dry line will not let it keep running.

[foshi]

will run on easy start enough to prime the carb though 

[NonMember]

1 hour ago, foshi said:

will run on easy start enough to prime the carb though 

That entirely depends how good the pump is and how dry the pipes are. If it's been left long enough to dry out, a weak pump may not self-prime on the cam and will need the extra stroke of the hand prime lever to get the first glob of fuel into it.

[foshi]

 if been left a long while  your correct had that same problem paul

[iana]

Swapped the plugs over today, the plugs were a on the black side, the plugs spark ok, will replace the dizzy cap and leads in due course. Checked the fuel pump and it does pump (on turning the engine over and on the priming lever). Car turns over well but will not fire. Not sure how to check the carb but despite cranking the engine over there’s no smell of fuel on the plugs - I’m guessing the carb could be blocked. 
 

It’s a Stromberg, the choke doesn’t seem to be working properly (the movement is limited) and needs checking. 

[johny]

One trick you can try on a stromberg is blow into its overflow hole using a plastic tube. You have to remove the air filter and the hole is in the top of the front face so if you blow in this you will pressurise the float chamber and should push either fuel or air out of the jet which you can see through the mouth of the carb.

If nothing goes through = a blockage, if air comes out = the camber is empty or, if fuel, then the problem lies elsewhere. In the second case the float valve could be stuck shut but by removing the fuel line and blowing into the connection you can check this....  

[Pete Lewis]

what type of strom  is this      a CD150 ??   has  have what i call the thames barrier idea that raises the needle and blocks the throat 

or a later CDS  which has a starting valve on the side with discs inside to meter fuel ??

Pete

 

[iana]

It’s a stromberg cd150

[iana]

Just had a tinker and see what I can work out (not very successfully). If I take the air filter off and spray open the accelerator flap and spray ezi start in it will fire but will not run. All very odd as the car used to be brilliant at starting. Only difference is before it was parked on the flat now it’s on a slope. Checked the fuel pump and that is pumping fuel when cranking. Could it be as simple as crud in the float chamber?

Picking up on Pete’s comment re Thames barrier type that makes sense seeing it now. It is lifting the needle not by a small amount. 

[Pete Lewis]

yes the ramp has to roll up fully to lift the air piston fully by the max amount the ramp/barrier  rotates to give the lift and enrichment 

might help if you disconnect the cable and roll the lever fully is it sticking etc   

Pete

 

[iana]

Checked the choke, the first one is no choke, second is maximum choke and the third is the extra by moving the linkage on the side of the carb

[johny]

Ýes the choke looks fine however is your air piston sitting down hard on the bridge? When you lift it manually and let it drop there should be a slight clonk as it hits the bridge....

Also Ive never seen the air piston with its small needle screw hole showing at the front like yours. It might be your model of carb but are you sure the piston is orientated correctly and the rubber diaphragm lugs sitting as they should in both the piston and lid recesses?

The float chamber vent I mention earlier is that one just next to the LH air filter fixing hole.

[foshi]

so when you  spray the easy start in do you have it on full choke . if it fires you have a fuel problem could be a weak pump. spilt diaphragm . could try gravity feeding the petrol just to eliminate blockages 

[dougbgt6]

I suspect fuel blockage, the dread rubber slivers! Take the reservoir off, the valve off and clean it out. A blast under the cold tap will do it. Removal can be done in situ, but fiddly. 

Doug

[johny]

Note: if you take the carb reservoir bowl off you will almost certainly need a new gasket because the old one will stick and get damaged. Theres two types of replacements available. Also the o ring that seals between jet assembly and the bowl may need replacement so its good to buy it at the same time👍

[iana]

I think I’ll probably remove the carb and clean it out. Annoyingly I doubt I’ll get the bits before xmas now. I guess I’ll be back with more questions over Xmas.

[johny]

well unless its been done recently therell certainly be muck in there and you might as well change the other o ring on the jet at the same time plus check float level etc. Saying that Id rather blow through it first but I suppose if you have it apart at least you can cross it off the list.....

[dougbgt6]

I've done it quite a few times without damaging the gasket, always had new ones to hand, but if it comes off clean it can go back. I once did it one day and had to do it again the next day, infuriating!  Gaskets are almost certain to tear if the carb has flooded and the gasket wet for long periods. But, do it now, see what you've got!

Doug

[Pete Lewis]

another way to confirm piston orientation  remove top cover and look down the air piston the two holes in its base must be towards the manifold 

as Jonny syas  there are two lugs to determine the positions   one  on the inner dia   fits a recess in the air piston under its clamp/damper ring   

the other is on the outer dia  fits a recess in the main body location diameter 

as for gaskets most kits contain a few as there are small changes over the years  and you must check what you fit is the same as removed  as corners change and you will make a leaker 

Pete

 

 

[iana]

Is there a really basic guide to cleaning / service a stromberg cd150. I’m also thinking that’s shows all the components.