Turning left causes it to stall......?

[Cosmic88]

This is quite odd and I have a few theorys but I am reaching out to the collective minds here.

It's a 2.25 with Zenith 36 1V carb and I have a new (3 months) old fuel tank. Fuel filter is also 3 months old. It runs fine up and down hills and no probs when I make a sharp Right turn but as soon as I make a sharp-ish Left hand turn the engine is starved of fuel and I must either increase revs, pump the accelerator or leave it in gear and hope for a rolling restart.

The carb has been cleaned recently and there are definitely no deposits or residue on the needle or any of the jets. This left hand-cut-off thing is about one week old.

Makes navigating through town interesting as I plot my course with as few left turns as possible.

[greenmeanie]

Look at the orientation of the floats. My bet is a sticky float that gets into a certain position on the left hand turn.

[LaneRover]

How quickly into the sharpish left turn does it happen? If it is pretty immediate I would suspect something other than fuel.

If it takes a llllooonnnnggggg sharpish left turn then I would agree that it could/would be fuel related.

Any chance any of your ignition electrics is loose? Something that makes a connection most of the time but left hand turns make it lose a good connection? I once had a low tension lead that ended up being a problem with my 65. When I was looking for the problem it practically came off without pulling (corrosion) but the truck ran fine unless I hit a bit of water (on the street not fording a stream).

Good luck figuring it out!

Brent

[gudjeon]

Try pulling on the carb's air horn while it is idling and see if it will stall. I had a Zenith that would stall on me every time I braked while backing up. The rearward inertia of the intake elbow and hose pulled it just enough to open up the warp to cause a vacuum leak. Yes, even after I rebuilt it and everything was tightened up. It turned out to be the famous Zenith warp.

Once fixed, it worked many years with no problems.

[Cosmic88]

Greenmeanie --- I (for the second time in 4 months) disassembled and cleaned all jets, needle and checked vacuum (to dizzy) and the pump jet and accelerator diaphram.... all of these are clean/working and in good condition. The float was in good condition, moved freely and was set to the correct (33mm) float height above the emulsion block gasket.

Brent---- I have checked all ignition related electrics and connections. I very recently cleaned contacts on the LUCAS fuse blocks and checked the coil connections and found no problems with contact.

Gudjeon--- I'll try that to see if I am getting air leaks around the mating faces. 4 months ago I flattened all the faces on my famous Johnnie Walker sanding mirror and there were no probs with stalling / air leaks. However, I am in Florida and it is hotter than the place Mr. Lucas is from so maybe I have another bit of warpage but so soon after flattening is hard to believe... but possible.

This sputtering feels more like fuel delivery than electrics since halfway throught a turn the engine slows but with throttle pumping it will stay alive just enough to keep turning over until I get back on a straightaway and it comes back to life. But this is hard to imagine anywhere else (ie. filters, pump fuel tank...) other than the carb itself. I say this because the sputtering starts after about halfway through a turn which is about 15-20 feet. at about 15 - 20 mph this diastance is about 1 second, caused by slight change in inertia. (Math nerds need not dispute that previous calculation)


Thinking about switching to a Rochester or Weber.... as much as I hate to see the original Zenith go by the wayside I need reliability. A very similar situation occurs whenever I am off-road and the truck is at a roll angle of more than 30 deg (either way) and pitch angle (fore and aft) of more than 40 deg.

[LaneRover]

Is there a chance that your carb float is set too low so you don't get enough gas in there and it quickly 'starves' the carb on a left hand turn?

Have you tried jacking up the left hand side of the carb to see if that does the same thing? Or drive it on a side slope to mimick the same thing?

[Cosmic88]

have not yet tried jacking up the left side of the vehicle. I have however, been off road and the vehicle routinely stalled when the roll angle exceeded about 30 deg. After some research I believe I am switching out the Zenith to a Weber 34 ICH. Others with the same or similar problem have converted to the weber and the problem went away.

Do I need a conversion kit of some sort when swaping the Zenith to the Weber??

[LaneRover]

Or get wedge shaped piece that leans the carb to the left . . .

[scott]

too bad, if it was right turns you could go nascar and your problem would become a mute one

[KevinNY]

Maybe it doesn't like NASCAR?

[Tim Smith]

I used to have a problem where turning left (are was it right) would cause the truck to slow down. Of course turning in the opposite direction the truck would speed up.


Turned out the steering box connection to the frame was loose and torque of steering was bending the bulkhead in one direction or the other. Since the throttle linkage is attached to the bulkhead, I put two and two together and figured it out pretty quick.

[Cosmic88]

funy thing...

Les suggested the same thing. Checking the bolts and mount for steering box again tonight. Last night I did notice a VERY small amount of movement in the throttle linkage when I turned the wheel with the vehicle standing still. The movement was about 1/8" deflection to the left and right of vehicle. I sort of expected this as the friction on stationary tires could cause a slight amount of movement in the steering mounts but this did not appear to be enough to cause the throttle linkage to close the throttle.

Back with that update....

As far as the NASCAR option... if anyone out there wants to sponsor my truck feel free to send cash.... no third party out of state personal checks please.

[Cosmic88]

ok then....

I beieve I have eliminated the steering box movement as the possible problem. And I am 90% certain it is not an electrical issue. the only time the carb slows (with the air intake elbow removed to eliminate flexing of the carb body parts) is when there is inertia placed on the vehicle during a left hand movement at coasting speed. During a very slow turn there is no interruption in rpm's. Now I'm off to remove the carb and check the floats again.... weeeeeee

[bobzinak]

stalling

you didn't mention fuel pump....check pressure and delivery. bobzinak

[Cosmic88]

fuel pump

I am getting plenty of pressure / flow. Do you think a single direction (left) change in lateral inertia could affect the fuel pump and how effective it is?