valve adjustment

[yank]

My SIII is running very rich. If the valves are not adjusted correctly is it possible to get soot out of the exhaust pipe?
The carb has been recently rebuilt and the timing done.

[scott]

valve adjustment is pretty simple. only takes about 10 to 15 minutes. but i's suspect mixture screw setting?

[yank]

I did the valves when I had the head off. It was the first time I have ever adjusted valves so I thought maybe I did something wrong?
The carb was rebuilt when the head was off also. I have messed with the adjustments on the carb and it doesn't seem to help any.

[scott]

what carb? i've a weber 32/36 dgv. i don't know squat about the others

[Nium]

Why did you have the head off?

Did you follow the procedure for valve lash adjustment as outlined in the manual?

Any other symptoms?

[yank]

The head gasket was bad. I followed the factory manual for the valves.
It has a Zenith carb.
Befor I had the carb rebuilt it started instantly but would only run with the choke half open.

[Nium]

Guessing not valves at this point but carb.

Have you run through the checklist for "Excessive Fuel Consumption" in the sticky thread for the Zenith?

[Bertha]

It has a Zenith carb.


This may be your problem. Zenith's are known to load up a bit at idle. IMO they are not the greatest carb . I have never had much sucess with rebuilding one-while they seem like an easy carb, I have yet to get one to run as well as a weber or the solex that came on early trucks. Even though I like to keep things original, any truck that I have had that came with a zeniths, I replaced it with a weber. Weber has its own drawbacks(tend to run a little flat IMO), however they always seem to work fairly well.

[kevkon]

It's been my experience that some carbs just don't perform well after rebuilding. It has a lot to do with the design and the fuel circuits. Also, it seems there are many different ideas as to what rebuilding a carb amounts to. For example,we use to coat some of the non metallic floats with model airplane dope to seal them as they became porous with age. Failing to do so meant the fuel level in the bowl would never be correct. There are also fuel circuits in the body which can wear from use or even become clogged in the course of cleaning. Sometimes it's just wiser to invest in a new carb.

[yank]

I wish I had not already invested in the old one.

[czenkov]

Have same carb and issue. Drive it and it starts struggling to idle - then dies. Restart blows black smoke runs good for a bit ( a very short bit) then struggles once more and dies. Got told today that it is drawing fuel from another place (circuit). Used a term for it but cannot remember. Good luck. I am rebuilding a Weber for mine - hopefully the Weber will solve THAT problem - then on to others!

[Nium]

When the carb was rebuilt was it annealed? After annealing were the mating surfaces checked to insure flatness? If they weren't flat (hardly ever are on a Zenith) were they run across a fine piece of sand paper taped to a sheet of glass or mirror until they were?

Zenith's use to warp because they weren't properly annealed at the factory after casting, at least that use to be the case, there use to be threads that discussed annealing I'm not sure if there are anymore. The warp would cause leaks of air around the mating surfaces that would lead to unhappy Rovering.

[gudjeon]

The Zenith carb will idle rich if the float setting is not spot on. The slightest bit higher in the float bowl cases a very rich idling. I am finding I have to readjust the float periodically as it goes out of adjustment with prolonged rough terrain. :D

[czenkov]

Ok, half serious half not. Does the rough ride of the Rover constitute rough terrain :D? "Bouncy" is the nice way to put the ride of my rover. 1/4 cab and a distinct stinkbug posture. Not to move the thread topic from carb to springs.

[gudjeon]

My Rover has more of a bark beetle stance, in that it is more or less level. I find that rough roads, having large rocks sticking out like "dead heads" when the dust and sand has blown away, are smoother to travel at speed. I am talking about rougher, more bouncier motoring while traversing such features like removed culverts, fallen logs, washouts, and good sized rocks. This is, of course, done at a crawl and over time my Zenith's float setting changes just ever so slightly to idle very rich.

[dgaley]

can anyone give me the right way to adjust the mixture screw ?

[Nium]

dgaley,

If you want to adjust the idle mixture on a Zenith then I'd recommend reading through the sticky thread at the top of the "Land Rover Series I, II, IIA, III" forum labeled Zenith Carburetters Service Bulletin (http://www.roversnorth.com/forums/showthread.php?t=3121). Start a new thread if that doesn't help. A new thread would let others know you wanted to know something different then what's in this thread.

FYI. The idle mixture screw only controls idle it has nothing to do with fuel delivery past idle.

Welcome aboard dgaley!
Cheers!