Fuel starvation and coughing

[Markieboy1]

I just bought my first Rover 1965 lla. Starts great when cold. When hot it blows black smoke on longer start. When engine is hot while driving it coughs, sputters like its being starved for gas. Its okay at idle, or when revving at stop. However when under a load the engine seems like its not getting the fuel. I removed fuel pump, inspected and replaced. IT was pumping fine. The new see thru in line fuel filter is showing lots of fuel, no sediment. The carb (Weber) is new (according to previous owner). The fuel seems to boil in the bowl. Any help appreciated. Thanks.

[Jim-ME]

Sounds like it is running rich to me or your timing is off. Are your plugs showing the it's running rich? You may also have a bunch of crap in the fuel bowl. Check your plugs first then see what the inside of your fuel bowl on your carb looks like.
Jim

[Markieboy1]

I took out spark plug for examination. Plugs are white. Running really Hot! Fuel bowl is clean. I took out the jets and blew them out. They are clean. Still runs terrible. Black smoke at start up when Hot.

[Jeff Aronson]

Here are a few questions:

1. You're right that white residue on the plugs means you're running quite hot. That can mean either too lean a mixture or timing that's too far advanced.

Timing too advanced will make a car hard to start, particularly when hot. That will result in you pumping a lot of gas in while trying to start it - thus the black smoke on start up, which is unburned gas.

2. Clean and/or replace the plugs. Gap the points first and make certain they're right on the top of a lobe when you gap them.

Better yet, if the points are old, replace them with the correct ones for your distributor. Don't try a NAPA or similar store - they do not cross list point sets accurately for Land Rovers. I once helped a fellow travelling through Maine from Wyoming who had similar symptoms. His points were the wrong ones for his car, but a parts store had told him they would work fine.

After this is done, then time the car. An incorrect point gap or pitted points that are correctly gapped will cause a sputter that seems like a fuel issue. I know this because I once replaced a Weber with another one when the problem was bad points.

3. If you still have a problem then turn to the carb. The Weber is quite reliable and there is no real high speed mixture adjustment. I would remove and clean out the filter that sits inside the 3/4" brass nut on the bottom side of the carb bowl. Then I would unscrew the top cover of the carb and slowly lift it to one side so as not to tear the gasket. The carb float will come up also. Peer inside the bowl and look for rust colored sediment. If there is ANY, clean it out with a paper towel and carb cleaner.

It's likely that some of that stuff is now partially blocking an orifice in the carb. While this is usually a problem that manifests itself with stalling, you might have a tiny bit of junk in the wrong hole. There are two tiny brass jets, side by side, on back side of the bowl. Use a thin flathead screwdriver to remove them. Spray carb cleaner through each one and into the hole they scew into. You'll see some shoot out of another orifice. One screw is the high idle jet and one is the low speed idle jet [sorry, I don't remember which is which]. You can also remove the idle mixture needle screw in the back of the carb and spray into that hole, and the same with the jet underneath another screw on the side of the carb facing the valve cover.

BTW, compressed air works even better than the carb cleaner. If you have one of the cans of air for computer keyboards, it will be fine for this task.

Good luck and let us know.

Best wishes,

Jeff

[Terrys]

I agree with Jeff, that it certainly sounds like a points/timing issue.

[Markieboy1]

Thanks. I will try these solutions. I have never done Points, nor do I have a timing light. But willing to give it a try. I bought an electric fuel pump but will hold off installing that until I see if these other solutions work. Many thanks.

[Markieboy1]

Since I had no means of getting with anyone re: timing tonight, I installed (tempory) the electronic fuel pump just to make sure that there was nothing wrong with the mechanical fuel pump. Pumpin fuel, still not solving problem.
So.. okay if there is points/timing problem I cannot understand why it would fire up IMMEDIATELY when cold and run great until it gets hot. Any answer on that one? Tomorrow I guess I need to either find someone (not a chance around here) who knows how to fix the timing. or unless you guys have some instructions on how too. By the way, what is the dial (knob) on the side of the distributor for. Thanks

[Jeff Aronson]

As you demonstrated, your fuel delivery is not the issue in this gase.

When you start an engine cold, you generally use a choke and that aids in the initial starting process. You might have a weak spark because of the points, but a dry cylinder and the choke help overcome that when you first start the car.

As you drive it, the heat generated by the engine removes the need for the choke. Now it's starting only on the spark-at-the-right-moment itself; indeed, if you try and choke it you will likely flood the engine instead. That means that the spark needs to be strong and firing exactly at the right moment - thus, the need for good points gapped correctly, and exact timing, not to advanced and not too retarded. Also, under a long run every metal part on the engine expands a bit, so it's less tolerant of imprecise firing than when it is cold.

The timing is adjusted by twisting the distributor right or left. There's a 7/16" nut underneath the distributor; loosening it will allow you to twist the distributor and thus adjust the timing. While you can do it without a timing light, I would not recommend it because it's too easy to overdo the adjustment without a light.

You wrote that you car pushes out black smoke when you try to start it hot. When that happens, it implies that you're opening the choke when you're trying to start it, or that a lot of unburned gas is pouring out of the carb and into the cylinders. Unburned gas can be a sign of poor ignition, such as a weak spark at the points, or timing that is off.

The other symptom is your description of white residue on the plugs. That's a sure sign of hot running. Assuming your cooling system is fine [you have checked the coolant level, right?] then the only unusual heat level inside the cylinder would come from when the pistons are firing.

(BTW, are you losing coolant without spotting any leaks? That could be a sign of a head gasket problem; that would cause hot running and hard starting, too. )

That said, there are steps you can take. Do you know how to gap the points? If not, ask and someone will help you. Do this before you deal with the timing.

The dial on the side of the distributor is a sure sign that you have an original Lucas distributor. It's the fine vacuum adjustor for the distributor, used normally to fine tune the timing or make adjustments for poor quality gasoline. Many no longer function even when you can turn the knurled wheel.

Since you have an original distributor and you just bought the Rover, do you know how old the cap and rotor are? They are an easy replacement and do affect the starting/running of the car. Given the symptoms you describe, I don't think they are the sole issue here, but they may contribute to your hard starting [but not your hot running] when hot.

A strobe timing light gun costs about $20 and is very easy to use. It comes with two clips, one the positive and one to the negative post on the battery. There is a third connector that goes over the spark plug wire to the number 1 plug [closest to the radiator]. Lean over the radiator and look down at the crankshaft pulley on the bottom of the engine's front. You'll see a pointer over the pulley. Run your fingernail over the circumference of the pulley and you'll feel a notch on it. When the pointer lines up with the notch, then you know the car is essentially correctly timed. You'll see some lines on either side of the pointer; those represent advance or retarded limits to adjust for gasoline octane.

Start the car and click on the trigger of the timing light. That starts the stobe light. Lean over the fan and point the timing gun at the pointer. If you're lucky, you'll see the notch shine up at you when the light strikes it. If the notch and the pointer line up when the strobe hits them, your timing is fine.

If it's not, then stop the car and loosen the distributor clamp nut somewhat, leaving enough tension so it's not moving on its own. Start the car again and slowly turn the distributor; with the strobe light on you'll see that the light hits the pointer/notch more exactly. Once they are lined up properly, then tighten the clamp bolt and you're all set.

One very unlikely - but possible issue - is the coil. If after warming up the coil is hot, almost too hot to touch, then it is failing and that would show with a hard start and bucking/spitting at speed. A failed coil would not allow the car to start; a failing coil would cause sputtering under load, cold or hot. Because your car starts and runs fine when cold, I doubt the coil is the problem here.

I hope some of this helps - take things step by step so people here can help you.

Best wishes,

Jeff