88 dies after warm up

[sayers]

Help, i have a 74 88. I have installed a new zenith 361v carb. fuel pump and tank. The truck starts up and runs great until it warms up. When I come up to a stop light or have to stop the truck dies.It starts right up but I have to give it gas for it to keep running. I have adjusted to idle and tighten the bold holding down the adaptor and carb, with no difference. Any help with be great. thanks

[a109]

There's probably some dirt in the idle jet.
Any new carb needs to be stripped and cleaned and the float level set up for the application. Carbs are not out of the box bolt on replacement parts.
John

[Momo]

Sounds like a classic Zentih float level problem. Your float may be adjusted wrong, or the float is defective and gasoline has leaked inside.

Zenith floats used to be braised tin and brass, but are now cheap HDPE plastic crap. They often have a bad seam out of the box. Take the float out and shake it. If you hear gas sloshing you need a new float.

I doubt you have a dirty jet.

[a109]

I doubt you have a dirty jet.

Care to explain? Surely with the installation of a new tank some dirt is to be expected.
Besides if the carb is to come apart to examine the float level a cleaning of the jets is such a minor thing to do.
John

[Momo]

A dirty jet is dirty whether the engine is cold or warm.

If the float is bad (very common on a new Zenith- 3 out of the last 5 floats I had were defective) the truck will typically start fine, and run fine for awhile undisturbed, but the bowl will be too full at a given point and the fuel will slosh into the throat when the truck stops and kill the motor.

Open throttle will abort the stall given higher vacuum/airflow but truck will still stall when rolling to a stop without a little throttle to counteract it.

Once he takes the top cover off the carb and notes how high the fuel is, and checks the float for fuel ingress, we'll know if I'm right or wrong.

Dirt in a new tank would surprise me- and the pickup tube filter screen and fuel filter should take care of that in any event.

Also, the 36IV is set up for Land Rovers at manufacture- it's a good idea to confirm float level but stripping a new one down is unnecessary.

[jp-]

I got $20 on Momo...



Flame On.

[singingcamel]

are you running a inline fliter,if not i would..
i would agree with adjusting the float level and clean the jet..as previously posted
www.singingcamel.com (http://www.singingcamel.com)

[sayers]

Yes I am running a new inline filter, How do you adjust the float ?

[LaneRover]

I had the exact same problem with a 'mostly' 73 SIII that I still have. In the end it seemed to be the fact that I hadn't tuned it up in awhile. Once I tuned it up and had all new ignition parts it ran like a champ again. Of course it was probably so finicky because it was a bit of a clapped out engine that tended to burn A LOT of oil.

LaneRover

[a109]

A dirty jet is dirty whether the engine is cold or warm.


Dirt in a new tank would surprise me- and the pickup tube filter screen and fuel filter should take care of that in any event.

Also, the 36IV is set up for Land Rovers at manufacture- it's a good idea to confirm float level but stripping a new one down is unnecessary.

Yes a dirty jet is blocked cold or warm But the choke will offset the effect.

Unfortunately screen and filters may not catch particles small enough to block the idle jet. New tanks may well have manufacturing/shipping/storage/installation debris in them.

I 've encountered enough new carb problems not to install one out of the box.
So as a matter of course I always check the float level and the needle valve action. Naturally a jet blockage would only show up later but if the float level is to be checked because of a problem it's only a 30 sec job to blow out the jets. so simple and quick it should be routine.

John

[a109]

Yes I am running a new inline filter, How do you adjust the float ?

You remove the top cover and hold upside down so the floatarm is resting on the needle valve and measure from what is now the top of the float to the cover (with the gasket still in place) this should read 1 5/16 inches.
It is adjusted by carefully bending the arm that touches the needle valve.

John

[sayers]

thanks John and marc. I will let you know what happens. steve

[sayers]

I took the top of the zenith carb. off and checked the floats. They were both off, so I adjusted them to the proper level. I also found that the set screw on the idle was working its way out of adjustment when I drove the truck due to vibration. The screw is suppose to be held in place by a lock nut, but on this zenith the nut is very loose and would not hold the screw tightly when it was in the plastic protective cover. I used some loc-tight and I think my problems are solved. I just find it hard that when you get a brand new unit the workmanship is not up to grade. anyway, to all thanks for the great help.

[PH4]

I do have the problem of my Zenith stalling the engine when I stop fast but this goes away after it warms up. What I do have a problem with is it idles great and no problems when you give it gas in neutral but sometimes when under power it seems to sputter or hiccup. Any suggestions as to cure? No telling what day it will decide to do it. Sometimes fine sometimes not. The 2.25 does not run well when you give it much more than 10% of the throttle. Any help much appreciated.

[Tim Smith]

I do have the problem of my Zenith stalling the engine when I stop fast but this goes away after it warms up. What I do have a problem with is it idles great and no problems when you give it gas in neutral but sometimes when under power it seems to sputter or hiccup. Any suggestions as to cure? No telling what day it will decide to do it. Sometimes fine sometimes not. The 2.25 does not run well when you give it much more than 10% of the throttle. Any help much appreciated.

Check the intake air flow. My jimmied air intake had a flaw in the design as one of the plumbing connections in the middle was too restrictive. I think it would cause a vacuum build up on hard acceleration that would cause the truck to actually bounce off the clutch springs while the engine was sputtering.

The effect was really anoiying... You are in first gear and trying to accelerate from a stop light but the truck would bounce off the clutch springs and accelerate ahead of the engine. Then the truck would slow down again when it bounced of the opposite side of the clutch (like engine breaking) till the motor caught up again. Back and forth, back and fourth until the motor was up to full speed.

I was perplexed until I tried running the truck without the air filter and found it would accelerate as it should. It's right up there with school busses and dump trucks now! :thumb-up:

So check the air filter for flow. It could directly choking the truck or effecting the vacuum advance. Thats my guess.

[a109]

If the carb seem s OK and problems still seem to be fuel related have a close look at the airfilter to carb hose. They have a tendancy to collapse internally when old. It may not show up externally.

John