No good again! Bis wont idle...

[poxxxy]

Well drove it back to my parents today and the car would barely rev... seemed to run better with the choke on and seemed to pickup.

Went to drive it out with a friend and idle was all over the place and couldn't keep it running without choke or high idle . Seemed to be missing to.

Took spark plugs out and they're a little white so probably running lean.

Not sure what it is... These carbs seem to be a mystery to everyone as I've asked for some solid help on how to set them up and never got a decent reply in any language. Not even sure what jet is which and what all adjustments do .

My guess at the minute might be a blocked idle jet but starting to think that's the end of this engine... 1 day after being MOTd!  Would be easier to legally perform some kind of conversion now though with tax and MOT I guess.

[poxxxy]

Seems to rev freely when parked up with the accelerator but when it was under load it was another story

[Henmiester]

Have you checked the float level. Mine was like that. Combination of over flooding the engine and timing being out. Have you tried setting the timing by doing while static?  Does it do it while cold or when fully warmed up. Simon.

[poxxxy]

Timings all good, float level was set all OK although there was a little crud in the bowl again .  Not sure I should try different measurements on the float to see if it helps. Wondering what the best way to clean it all is at the minute.

Idle mixture screw setup just doesn't seem to work... engine will die if it's too far in but then it doesn't change no matter how much it's screwed out. No real peak rpm.

[Henmiester]

Are all the vacum pipes connected properly. I would also check the distributor and see if the weights move when someone revs it.

[wsmitwil]

Are all the vacum pipes connected properly. I would also check the distributor and see if the weights move when someone revs it.

These weights were what was wrong with mine sounds similar problem,

[gammakeith]

Mine was running quite lean.  I stripped, cleaned carb and blasted it all with my high pressure airline and all was fine afterwards.  I didn't spot anything that looked clogged but there are a lot of fine drillings.....

+1 on checking for a vacuum leak.  May also be worth checking that the carb flanges are flat when it is off.  The only other place where air may be getting is is from worn spindles?

My mixture screw did produce a change in rpm.  I started with 1.5 turns out but it was quite poor.  I ended up turning it out a couple of turns when all of a suddon ther rpm shot up and it idled nicely.  I left it there and its been fine since (I don't have a CO meter).

The carbs are complex but as long as it has the right jets in then there is not much to go wrong.  I bought the Haynes Weber carb manual which is helpful though doesn't cover the exact model on the Bis.


Keith

[poxxxy]

This is happening when warm now, i've had it before when it was cold but when it was warm it always behaved...

Vacuum lines all look good... vacuum advance appears to work (not sure what weights these are exactly but the vacuum actuator moves something.

Decided to take carb apart and fit new diaphram, valves, etc... may try setting the float to weber specs rather than the ones I found for the FOS online.

[Gadge]

I personally think you have an ignition problem.

I've had similar problems with mine at the beginning. My problems centred around the distributor weights. I could see the vacuum advance turning the base plate but when I removed it a spun it by hand you could hear the weights clattering about. Couldn't quite work out why they were making such a noise as they were still attached but clearly the springs weren't holding the weights in almost as if the springs were weak. A different distributor solved that but that distribubtor didn't last long either as the pin holding the points in came away from the bases plate! DOH! So if yours is fitted with a ZELMOT dizzy then personally I'ld give it a thourgh inspection as I belive they are not the best quality.
 
When all this was happening with mine I too thought it was a mixture problem at first and just like you found it would almost cut out when screwed in but no difference when screwed out. I have an AUTODATA carburettor manual that covers the weber carb fitted to the BIS so I set it up to that only for the problem to still be there.

[poxxxy]

I need to find a new dizzy and coil really... then everything has been replaced lol.

It is a Zelmot unfortunately, but will have to have a good look again at it tomorrow!

Started stripping it today to see if I could identify anything.

Turns out the float was cracked in two places... not sure exactly what had caused it to fracture... fixed that  and replaced back in the carb and proceeded to use up the rest of the carb refurb kit I'd bought and replaced diaphrams, o ring on the idle mixture screw... put it back on the car and had it running a bit but the exhaust was more broke than originally thought... and with the racket it was making it was really hard to tell exactly how the car was running. Not sure it wants to idle properly still. Anyway... my dad welded the exhaust back up, may put it on the car tomorrow and see how its running again... but also may continue to strip down the engine tomorrow to possibly put that copper head gasket from Piotross on .  Guessing the head nuts need retorquing already though as most things seem to have managed to work loose... I think loctite is in order on everything!

[Gadge]

Yes give it a torque up after 500 miles. A pain really as you have to take the manifold off which means draining the coolant. I too have the same copper head gasket from piotross so I'll be very interested in how you get on with it

[poxxxy]

Got the exhaust back on but same issues. Rough idle all over the place and will cut out if at a normal idle rpm after giving the throttle a blip. Rpm just goes up and down.

Timing cover is leaking from the crank seal which I replaced... starting to get real pissed off with all of these crap "new parts" which just fit absolutely terribly. and cause me more issues than the original fitted parts. .

[poxxxy]

Well... not sure whats done it but managed a trouble free journey (kind of) back home... minus an incident at sainsburys after stopping to get fuel... really laboured to turn over and just wasn't having any of it... Had my dad come and rescue me...

Had jump leads on the battery for a while but still didn't want to know when turning...

Changed the negative jump  lead to the chassis where the battery connects and gave the van a good revving while turning the fiat... turned over very quickly and fired up again and managed to get home and have it ticking over enough to play with the idle and fine tune the high current draw vacuum boost on the carb.

Anyway...

Replaced the seal again with a "Corteco" one... and I still have another spare somewhere and added some loctite 648 bearing retaining compound to the edge of the casing... sorted the oil leak... now leak free finally!

Took apart distributor but bob weights etc were all ok.

Then picked up a new fuel filter as the old one was dirty as hell...

Put it all together and ran it for a while and after a bit of initial hesistation and a revving the car started to behave and managed to adjust the idle mixture...

Thinking I need to clean up all my earths now perhaps!? Alternator is putting out enough volts it seems although could be better, will have to check specs in the manual!