Technical Help! Idle all over the place ('69 850 Sport Coupe)

[theboycalledcrow]

After I managed to resolve my battery woes and get the timing correct on my engine, it now idles very irregularly. The first time I took it out, it was idling nice at just under 1000 rpm. A few hours later I took it out again and it kept stalling unless I pulled the choke at every stop. Even with the choke pulled halfway it would waver from 1000 - 2500 every so often. What could be the cause of this?

 

[timmycm850]

Hi Crow

from those symptoms i would take out the two idle jets from the carburettor and blow them through with air(you need to slide the jet out of the holder to fully do it properly, check your workshop manual for making sure you are undoing the correct part, often these jets are missed when a carb is rebuilt.

Tim

 

[timmycm850]

Also check to see if the carb pivot is worn, ive found with the 30dic whilst it has worn pivots it can make a difference how you shut the carb.

Tim

 

[theboycalledcrow]

I have no experience with Weber carbs, only SUs which are a different animal altogether. Do you guys have any resources/service manuals you can share?

 

[timmycm850]

Hi Crow

your probably best looking on ebay for a haynes type or other brand available.

this will give you good info like finding the timing marks and how to clean out the oil filter, also service schedules for reminding you to grease the kingpins etc

Tim

 

[FR85]

As Tim pointed out I would have a boo at the idle jet. Not sure if yours is a Weber 30 but the attached I hope will give you the general idea.

Take out the jet, comes in two parts along with a fibre washer, give it a good clean with compressed air along with a bit of a pokey with a strand of electric copper wire.

Hope the attached gives you a bit of help....

 

[theboycalledcrow]

Here's a good view at what it's doing. I'm not giving any throttle input at all and you can see the revs are all over the place.

https://www.youtube.com/watch?v=_zVu-N8SNQQ

 

[timmycm850]

Hi

looked at the video.

have you reset the timing with a strobe light.

Yep I would clean the jets first, don't go adjusting things that you havn't yet touched just clean the idle jets out first, unless you've set your timing with a timing light the timing may not be quite at the advance it needs to be, the specific timing can be slightly different for different models.

is yours a euro spec lhd series 2 or 3.

Tim

 

[theboycalledcrow]

I cleaned the jets, that steadied the idle a bit. But *where* it steadied was stili an unknown. Upon starting and after warming up, it purrs nicely just under 1k. After driving it around the block, it settles at just above 1k. Then after some freeway driving, getting on the offramp and downshifting to 2nd to get on a roundabout, it stalls. Sounds like I do need a timing light. I've also begun saving for a 123 distributor. I had one on my old Volvo Amazon and it was the best.

Mine is an Euro spec lhd series 2 (1969)

 

[timmycm850]

Yes, best to get the timing spot on really, "late" timing really brings the revs up on these engines and early timing stops the engine rotating.

it sounds like you may well have a worn carb mainshaft.

Tim

 

[theboycalledcrow]

Guess it's time to look for a local Weber rebuilder, as I don't feel I'm up to the task.

 

[timmycm850]

Yes, best to get the timing spot on really, "late" timing really brings the revs up on these engines and early timing stops the engine rotating.

it sounds like you may well have a worn carb mainshaft.

Tim

 

[timmycm850]

Where in the country are you based.

Tim

 

[theboycalledcrow]

I'm in central Milano.

 

[timmycm850]

you should be able to find someone local who is good with Webers.

Tim

 

[theboycalledcrow]

I've got a couple of places I'll be making calls to tomorrow.