Running Issues on 1600

[lanciamad]

Bit stumped about the running on my dads 1600 HPE, I know it's down to the carb but cant seem to solve the problem.
It had an issue with the automatic choke mechanism, which i'm pretty sure i've solved but there's still another problem somewhere along the line.
When its running right it goes wonderfully, but it has a habit of stalling occasionally, generally when hot. Sat on the drive, started, choke worked correctly as it warmed up, everything fine. Then turned it off, and back on again. Idle was constantly going up and down from 500rpm-1000rpm, turned off. Turned back on again and ran fine, but then after a while you had to put your foot to the floor to keep it running which then cleared, picked up and ran ok again after a few seconds.
Anyone got any clues? Is there any guide's to setting up the carb? I don't know much about carb's so the more basic the better.
Just after initial start up...


Warm...

Linkage pics, i've since tightened the nut seen loosened off...

[HFStuart]

Is the fuel return line A Still there and B Not blocked ?

[lanciamad]

Yeh it's still there, pipe was replaced a couple of years ago, i'll check for a blockage tomorrow if its stopped raining. It's due a new fuel filter and a couple of old pipes replacing to be on the safe side. What I did notice was that the filter is shown to be between the pump and the carb in the haynes but it's fitted before the pump, not that it makes much difference.
It's one of those frustrating problems when it's ok sometimes and sometimes not.

[Neil-yaj396]

I have the Haynes for the Weber carbs of this series but the bottom line is that due to the increasing emissions regs in the 70's there is little or no 'adjustment' that can be done beyond idle speed. The manual therefore largely deals with strip down etc. The jets are screwed into the body in the centre of your picture, might be worth taking them out for a check/clean. There is also a small filter near the fuel intake that is also worth checking.

Otherwise one of the rubber gaskets within the carb might have perished. Rebuild kits are available if all else fails.

[75coupe]

If it is of any help I'll list a few of the issues I have had with the std carb on 1600 & 2litre:

1. Blocked jets - the jets you see in the middle of the carb are very finely calibrated and consist of idle jets, main jets, emulsion tubes and air corrector jets - take them out and clean them, blow out with dry compressed air. Make sure you keep the right jets for the right barrel. ie. Jets for primary barrel (choke side) and secondary barrel, they look very similar for both barrels, but are in fact different. There are also "progression" holes drilled on the body near the throttle plate amke sure these are clean too.

2. make sure the float chamber is thoroughly clean and float level set - the jets are fed from the base of this.

3. I have had many problems in winter in the UK with carb "icing" whilst cruising, where the moisture in the air will actually freeze in the carb barrel, effectively blocking jets - this usually shows itself up as total loss of idle and dies on first barrel. The problem usually dissapears after the car has stopped for a few minutes as the under bonnet heat melts the ice! Make sure the thermostatic flap works on the air cleaner intake so warm air can be sucked from exhaust side.

4. Consider fitting a better fuel filter such as a fuel injection type - the cheap clear plastic in line ones are not always fine enough to stop the jets blocking. I've always run the filter between pump and carb, did not like the idea of it being before the pump, more chances of having an air leak.

5. Make sure the fuel shut off solenoid works properly - this cuts the fuel flow to the idle circuit and will cause stalling if not working/sticking

If all else fails fit twin DCOE's (only joking!) but seriously they are VASTLY superior in every sense than the original DMTR/DATR and give better fuel consumption, easier starting and far better running as well as more power and are not the hassle some people will have you believe...So long as the jetting is right.

Good luck

[Ammy]

It is perhaps worth adding to the advice given on Carb. cleaning that whilst the carb. is off and jets removed swilling a drop of petrol from side to side nearly always reveals some "bits" which lodge in the area of the pick up well. Whenever I service my carb. I spend some time swilling and am always amazed how may  "bits" appear  even after two or three swills.

[rossocorsa]

It is perhaps worth adding to the advice given on Carb. cleaning that whilst the carb. is off and jets removed swilling a drop of petrol from side to side nearly always reveals some "bits" which lodge in the area of the pick up well. Whenever I service my carb. I spend some time swilling and am always amazed how may  "bits" appear  even after two or three swills.

agreed I had a 1600 berlina played up a lot until I took the carb off and removed jets and adjusters and blew it all through with an airline nothing appeared to come out but ran like a dream afterwards shame I still don't have it 

[lanciamad]

Cheers for all the info. guys 
Unfortunately i'm going to be working solid on doing up my delta turbo (as I get it back tomorrow from the welders), so this will have to wait a while, but both this car and the turbo are booked in for the Bristol car show in a months time so i'll have to get around to it pretty sharpish, i'll keep you posted of any progress.
Luckily i've got a spare carb in the garage, so i'll have to pull it apart and learn what everything is and does one evening. I had a very nice and detailed email from Hutch that recons it could well be the carb float valve and seat need changing and the level re-setting. I have no idea what that is or how to do it, but i'm sure i'll soon find out

[WestonE]

Marcus

Check for airleaks leaning out the mixture by spraying wd40 at the base of the carb does the running suddenly improve?

Eric

[Neil-yaj396]

1. Blocked jets - the jets you see in the middle of the carb are very finely calibrated and consist of idle jets, main jets, emulsion tubes and air corrector jets - take them out and clean them, blow out with dry compressed air. Make sure you keep the right jets for the right barrel. ie. Jets for primary barrel (choke side) and secondary barrel, they look very similar for both barrels, but are in fact different. There are also "progression" holes drilled on the body near the throttle plate and sure these are clean too.


Good luck

Still having trouble with my car so stripped down the carb last week and blew everything through with an air-line, only to make things worse!!

However, I replaced the jets in my carb using the following instruction from the Haynes Weber Carb manual (32 DAT);

'...The primary main and idle jet are located on the accelerator pump side of the carburettor. The secondary main and idle jet are located on the choke side of the carburettor.'

Perhaps tellingly the jets were originally in the configuration suggested by 75Coupe (primary near choke), but my friend who last checked the carb for me confessed that he couldn't read the marks and just guessed when putting them back (it took the eyes of a 16 year old to actually read them!).

Who is correct???

[rossocorsa]

neil

did you remove the idle adjustment screws and blow through there as well? does mean resetting the idle mixture afterwards (use a colortune by far the best and esiaest method on older cars) but worth trying as I found that muck in there was an issue too. Not sure about jet positions if I get chance to check and have any info I'll post it later but that could be a major issue

[rossocorsa]

Neil

done in a rush bit rough and ready but hope they might help, sorry about the wonky photos but I don't have a scanner and no time to do nicely!!

https://www.dropbox.com/sh/nt7aq0ifpnnouw5/NjyQBSMYJQ

if you need any further info let me know and I'll try my best

[75coupe]

Neil,

It is easy to swap the jets around to see if they are in the wrong way around. I may have been misleading in my above description, I was referring to the choke flap rather than the choke actuating mechanism where the hot water pipes connect.

here is a picture:

[Neil-yaj396]

Thanks guys, all is explained. Unfortunately though, this means I've put the jets in the correct way but exacerbated the fault! Idle is perfect, but anything beyond is dreadful. I must have managed to blow some crap deeper into the main jet feeds somehow. Will take out the main jets again and explore.

[Neil-yaj396]

After the car had stood for a week while I pondered what to do next the fault 'cured' itself! The car has been started several times and driven hard for about 25 miles, running perfectly, or at least the best it has in my ownership.

My theory is that although my full carburettor clean up and blow through pushed some gunk into the main jet recesses, this has subsequently dissolved in the Redex rich petrol.

Not counting my chickens yet by any measure, but things never the less seem to be looking up at the moment. However, as my daughter has been the victim of most of the break downs, we are still going to drama class in the 'old' Coupe.

BTW the plan view photo of the carb above is brilliant, and totally lacking from any of the manuals that I have.

[Neil-yaj396]

My car was getting lumpy again at low revs after it's winter lay up. I've had all four jets out today and blew them through with an airline. Not 100% on the test run, but a marked improvement.

Hopefully a good dose of Redex will clear the rest.

[Neil-yaj396]

After running spot on since my trip to Italy in 2017 the 1300 conked out last week when doing some local driving. Restarting I had idle and full throttle again but nothing in between. I limped home 'popping and farting' then took out both slow running jets and soaked them in thinners for a couple of days. This appeared to clear out some gunk and once warmed up the car seemed to run OK.

Another long run somewhere appears necessary......

[HFStuart]

Another long run somewhere appears necessary......

At full chat too. The Italian tune up is not a myth.