Fuel/Air problem 1600CT

[chrissiefiddle]

last year we had a problem with an air leak on the engine. Ended up replacing the manifold gaskets only to discover that the cylinder head was leaking. Well £1000 later everything was fine and she behaved herself until late last summer when we were driving home from Norfolk. On the A11 we were trundling along at 55 with no problems until we got to a roundabout. As we accelerated away from the roundabout there was a popping and the engine died. My hubby managed to keep it running, slowly gaining speed and as soon as we got cruising again everything was fine until the next roundabout - and so it went all journey home.
we put the van away for winter and hubby has been out recently to try to diagnose the fault. He has checked the electrics, replacing the dizzi cap, resetting the points and timing. Still we have this annoying popping and faultering as you floor the gas pedal. Strangely it only does it once the choke has come off. He is worried we have another air leak and frankly it isn't driveable as it is. He has checked the manifold gaskets and the carb gasket, everything seems fine.
Now we either have another air leak (WHERE!!!!) or the van wasn't set up correctly when they put the engine back. My hubby discovered both the air bypass and mixture screws fully screwed in. He has played with it and some of the problem has gone but not all of it.
Is there anyone in the Bedfordshire/Herts area who knows anything about setting these up who can come over, check the settings and teach hubby how to do it himself ? We are not asking for charity (unless freely offered - we just want to get my van back on the road) so there may be a drink or pocket money in it for someone with the know how.

[dugcati]

if both the screws were right in then that sounds like the last 'mechanic' didn't know how a carb works!

If you can get the engine to run then a simple test for air leaks is to spray WD40 over the manifold where it bots to the engine and also where the carb bolts on, if there is a change in revs then there is a leak... SPRAY CAREFULLY! WD40 is flammable and if you spray too much it could ignite (after much smoking before hand though.

You mention roundabouts, is this related to the van cornering or just when the load/revs drop it wants to die? sounds like a carb/related fuel or mixture issue to me.

Simple things to check..

* Plug leads not damaged
* Dizzy cap - look inside - can you see black thin lines between the metal points - this is arcing and usually a sign of a worn cap
* Rotor arm, look at the copper connections, are they black/very dirty/missing bits/rough looking etc? if so replace
* Once the engine is warm......Have a look at spark plug number 4 (it's the easiest one to take out on the right nearest the dizzy), make sure you check with the engine warm and the choke off for around 10 mins as the plugs may well be sooty due to the normal enriching action of the choke!
* Will it run better/worse when cold - the choke being in effect could help point out fueling issues
* does it backfire/pop when you take your foot off the accelerator before changing down gears as you approach junction/roundabouts etc - if it usually points to the engine is running lean mixtures.
* Check ALL the vacuum pipes
* With the dizzy vacuum advance unit - with the dizzy cap,rotor and the plastic cover removed suck on the vac pipe nearest you (the one closest to the number plate) and check the internal plates of the dizzy move a bit, with suction on the pipe put your tongue on the end of the pipe for a couple of second and watch carefully that the plates don't slowly move back, it the plate moves back then the vac unit is on it's way out
* If fitted remove the idle stabilizer - this is a black box somewhere to the left rear of the engine bay, disconnect the joint the 2 cables going into it
* If possible/able to check the timing with a strobe - me/others on here can provide details if you are able do this
* Again if possible/able do a compression test on the engine

Hope these help in some fashion!



Doug

[chrissiefiddle]

Hubby here
I have checked the dizzi, points, and the leads, vacuum pipes, etc. I admit that I thought of the vacuum advance not working correctly so will try your suggestion of sucking on the pipe next weekend. Our old dizzi was a 009 centrifugal type that we swapped for a good(??) second hand vacuum advance dizzi. Definately not an air leak from the manifold rubbers and tried the wd40 trick on the carb to manifold gasket. Really worried that the head is 'loose' again. I agree that a compression test would be a good idea to confirm there isn't a leak on a head.
The problem seems to occur when you try to accelerate away from slow speed. If you plant the throttle it simply pops, backfires and loses power. The heavier the load on the engine (such as a hill or weight) the worse the problem. By backing off the throttle or slipping the clutch and keeping the revs up you can get it moving again. As I explained in the first note when the choke is on the engine seems to rev ok.
I agree that the carb is definately not set up right. I had a fiddle and got it running a tad better but no where near right. They recommend you start with 1 1/2 turns out (from fully in) on both the screws and then adjust from there which is what I did..

[sarran1955]

Hello,

Go mad...........









Spend the £6.60..................


















Fit a new condenser.............................

























Cordialement,

PS, Just back from ski ing in CT engined T25, max speed 112 KPH, and about 28 mpg. All on a standard motor, solex pict 34/4,


I will help you out......

[billy739]

doeset the ct come with electronic as standard?

if you are having a problem with the ignition HT side when you accelerate from slow , big load on engine and you will pull a good load from the coil , if not the best it can pop and miss but only under hard acceleration.

[dugcati]

does the ct come with electronic as standard?

Most of them had electronic ignition - I think the CZ and the earliest CT's had points

[sarran1955]

Hello,

If its any help, I'm running my CT 1600, (1980 year), with the electronic/mechanical Hall effect system completely removed. I run a standard SVDA distributor, points at 50 degrees of dwell, timed at 1000 rpm with vacuum pipe off at 8 degrees BTDC.

I will be posting photos and making a video this weekend, when I tune up a CJ after its initial 300 km shakedown.


Cordialement,

[dugcati]

* With the 009 dizzy the timing is set to 7 degree BTDC

* With the electronic dizzy the timing is set to 5-7 degree ATDC if it's left as is (timed to 7* BTDC) the engine will pink and you'll probably damage it before too long