• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

zs carb meetering needle position?

Share this page

M

Mack

Senior Member
Offline
Hello, I have been having trouble with my '76 B running too rich, I set timing, points,valve clearence, new plugs all the "other" stufff seems to be good... I've backed the meetering needle off quite a bit with no change, still blows black smoke out the tail pipe. I'm thinking maybe the meetering needle is bad and so I've ordered a replacement. My question is, what is the proper position of the brass piece that holds the meetering needle in the air valve? Thanks for the help!! Take Care, Mack /ubbthreads/images/graemlins/cheers.gif
 
I had trouble when I 1st got my TR6 with the ZS carbs, they were set WAAAY too rich.
So I got a trust carb adjusting tool and went to work one Saturday leaning the mixture out on each carb, at first a 1/8 turn then a 1/4 turn each time without apparent effect.
Eventualy I wound those suckers out (anticlockwise)several complete turns and voila, got it too lean so that it would stumble a bit under acceleration.
Then I tweaked them just a little richer and they're perfect now.
My wife likes it 'cos the car doesn't stink (her words) of unburnt fuel now. /ubbthreads/images/graemlins/iagree.gif
 
The needles do undergo a little erosion over the years so a new needle may help. I found a very good article on the internet regarding the replacement of ZS needles a while back. I found it through a google search and the title of the article is something like "needlepoint" or something similar. Anyway it is great info and if you can't find it I will email it to you. It is too large to attach to a post here. I experienced a similar problem when I first got my midget (smaller carb but same principle) I bought a new needle but could adjust it to the point where it was screwed all the way out of the adjuster with no affect. In the end it turned out to be a combination of plugs, wires, needle, and timing, plus a burnt valve that I haven't fixed yet...lol
JC
 
Thanks for responding, I found a good posting at the site you suggested. I changed the meetering needle with a new one from moss, it didn't look any different from the one I had. I installed it, reasembled the carb, backed out the needle two turns, and the car seems to running as rich as ever?!! Maybe some suggestions on what I should try next, could my fuel pump be pumping to much fuel into the carb? I'll take any suggestions and try anything at this point! Thanks, Mack /ubbthreads/images/graemlins/cheers.gif /ubbthreads/images/graemlins/cheers.gif
 
Well, it's like I've heard a thousand times here...most carb problems are ignition related. You can check your fuel pressure, it shouldn't be more than 1.5 to 2.5 psi...ish. Float level being too high can also cause a rich condition. Also check the normal stuff like the choke (a frequent offender) and the vapor absorption (or is it adsorption) canister. But seems like most of the problems that I've read about are caused by the ignition. Just so you know, you're not alone. There are tons of threads here with people struggling with ZS's that run rich. Let us know what you find. How do the plugs look after running them a little while? This can tell you if it is only a problem at idle or if it is all the time.
JC
 
JC, Thanks for the imput, I finaly was able to figure out it was the choke not working correctly, and I have to tell ya she runs greaaaaaaaaaaat!! What a blast to drive now! I can only imagine how much fun these cars must have been to drive when they were new! I am able to push the speed limit pretty good (when conditions are right) being a professional firefighter in NY, we tend to have an understanding with the police and they are great guys about cutting us breaks (as long as it isn't anything stupid)and I still can't get over how well these cars handle, it seems the slightest turn of the wheel will get you around the sharpest of turns. I hope you don't think I drive crazy all the time, only when oppropriate and conditions are right, along with a completely rebuilt front end, shocks, brakes five point harness and good tires, what a blast! Thanks again MACK
 
Back
Top