Sputtering/Chopper effect...

[NC Rover]

So for the love of me, I cannot get rid of the sputtering when it idles. It sounds like a helicopter. I've adjusted all the valves and checked them twice. They are perfect. I've adjusted the timing I don't know how many times trying to get it right. The carb is a Weber two-barral. It only has a screw for the idle. There is no screw for air mixture as I have taken it off and inspected it carefully.

Any suggestions on what to check next? I just replaced the whole exaust as well and that didn't help it.

[swaschka]

is it a perfectly repeating miss? If it is, determine which cylinder it is and work backwards through the system til you reach the common or shared portion of the system using known working components. IE: Once you know it is one cylinder replace things connected to that cylinder you know work on others such as plug, plug wire... well you run out pretty quick on these motors, but look at the cap internals etc. If it is not a perfectly repeating miss then go the other way. Vacuum leaks, faulty ign components. Replace with what you have you know works or systematically pull and check what is on the truck. Perfectly repeating misses are rarely caused by shared system components such as timing, fuel, air. Vice versa for random missing. Good luck. FYI my last series truck drove me to work every day for 5 years. Hardly ever did not have some intermittent miss or pop. Don't try to make it run like a Tundra, you'll go bald.

[NC Rover]

Yeah its pretty much the same repeating miss. I've replaced all the plugs, plug wires, cap, rotor...adjusted valves. I'm not sure but maybe the problem could be with the distributor. The carb may need fine tuning but I'm not a pro at tuning a carb. I've got the idle adjusted right. Its pretty frustrating. I'm not trying to get it to run perfectly smooth...but its annoying b/c it sputters along and never has full power.

[sven]

Which weber model # do you have?

[singingcamel]

Hows the compression?

[Jeff Aronson]

If you have another set of points, swap them out and gap them correctly, Make certain you don't have any distributor shaft wobble or you'll never get accurate timing or a smooth idle.

Singing Camel suggests you might have an "inside the cylinder" problem and it's well worth examining.

An easy way - start the car and then, using plastic pliers or insulated handle pliers, remove each spark plug cap. The engine running should degrade until you plug it back in. Try each cylinder in turn. If the engine note does not change, or changes hardly at all, on one cylinder, there's your problem. It could be a simple thing, like a bad plug, or more complex, like a poor valve adjustment [they do need to be adjusted every 15K or so], or worse, a burned valve. A compression test would tell you a lot more.

Another thing to try is to take a can of WD40, PB Blaster, or similar stuff, and spray around the carb body, the throttle shaft into the body of the carb, and when the engine is cold, the intake manifold. You may have a vacuum leak, which would cause similar symptoms. The intake manifold bolts onto the exhaust manifold, and as a unit, to the engine. So the gasket between the block and the manifold is really important and it can fail over time. You might just find that you have loose bolts which are letting air in; the carb is adjusting the constantly shifting amount of air.

The only Weber I'm familiar with is the single barrel so I can't be of great help. In general, Webers are reliable carbs but they can wear at the carb body area. I get about 100,000 miles per carb using the Weber, and find it easy to install and tune.

Good luck!

Jeff

[Tim Smith]

Helicopter sound? I bet you had a spark plug come loose.

[Bostonian1976]

is this sound just from the tailpipe? Mine has always sounded like this from the tailpipe (not that mine is a great example!)

[Eric W S]

Another thing to try is to take a can of WD40, PB Blaster, or similar stuff, and spray around the carb body, the throttle shaft into the body of the carb, and when the engine is cold, the intake manifold. You may have a vacuum leak, which would cause similar symptoms. The intake manifold bolts onto the exhaust manifold, and as a unit, to the engine. So the gasket between the block and the manifold is really important and it can fail over time. You might just find that you have loose bolts which are letting air in; the carb is adjusting the constantly shifting amount of air.



Carb Cleaner! Other aerosols like starting fluid can do bad things to the internals of your engine.

Find a local garage and see if they have a smoke machine. They will be able to tell you pretty quick if it is a vacuum leak.

Vacuum gauge works well to time the engine as well and you can tell a myriad of things about the internals as well. Google it.

EwS

[Rineheitzgabot]

I think that it would be okay to use the WD40 or PB blaster, as they are not nearly as flammable as ether. Additionally, the amount being deposited in the engine (only if there was a leak) would not be enough to cause damage.

[Eric W S]

I think that it would be okay to use the WD40 or PB blaster, as they are not nearly as flammable as ether. Additionally, the amount being deposited in the engine (only if there was a leak) would not be enough to cause damage.

Even a little bit of the wrong aerosol can cause a bad hotspot or even damage the piston/walls. Hence the cautionary advice.

My old mechanic had to order a new block for someone trying the same technique with PB Blaster.

Easiest way to do it is to have the engine smoked for 50 bucks and have the shop tell you what is leaking. No petroleum products gunking up the bay and you can move on to the next issue without standing around hosing your truck down...

Spraying is shade tree IMO...

[Jeff Aronson]

As one who constantly finds that the PB Blaster or WD40 can still feels quite full when the aerosol propellant runs out, I can't believe that there is enough propellant to cause damage. I've used this method on a lot of engines and did not make it up. A mechanic who's still in business showed it to me.

Carb cleaner has a propellant in it, too, or of course it would not come out of the can. I find that engine idle diminishes when carb cleaner is first sprayed into a carb. The opposite occurs when I use PB Blaster or WE 40. So if I want the rpm to increase when a petroleum product is sucked into a vacuum leak, I would stick with these products. This is not a long process; so not much is being taken into the engine.

I don't doubt that your mechanic had to replace a damaged block, but it's just not been my experience with over 20 different needy British cars :) that this diagnostic method has caused any damage.

Jeff

[Rineheitzgabot]

As one who constantly finds that the PB Blaster or WD40 can still feels quite full when the aerosol propellant runs out, I can't believe that there is enough propellant to cause damage. I've used this method on a lot of engines and did not make it up. A mechanic who's still in business showed it to me.

Carb cleaner has a propellant in it, too, or of course it would not come out of the can. I find that engine idle diminishes when carb cleaner is first sprayed into a carb. The opposite occurs when I use PB Blaster or WE 40. So if I want the rpm to increase when a petroleum product is sucked into a vacuum leak, I would stick with these products. This is not a long process; so not much is being taken into the engine.

I don't doubt that your mechanic had to replace a damaged block, but it's just not been my experience with over 20 different needy British cars :) that this diagnostic method has caused any damage.

Jeff

I agree with Jeff.

Additionally, this method costs less than $3, rather than an instant $50+.

For the past 15 years, I have been exposed to hundreds of diesel engines where ether was used (cautiously) to get them started, and not once have I seen problems caused by it. I realize that we are not talking about ether, and it is not a safe way of starting a motor, but I use the ether example because ether is much more volatile than less-refined petroleum products (which Jeff pointed out, actually make the engine miss, more than it accelerates combustion-propellent or not).

Besides that, who hasn't pulled a small block out of an old chevy using a hoist and an oak tree? :D Shade tree mechanics rock! :thumb-up:

[Eric W S]

I think it's similar to smoking. Some people get cancer others don't. To each their own I suppose. I'd rather pay the shop, order the parts from our host and move on to the next fun project knowing that one problem has been fixed.

[Jeff Aronson]

Eric, I understand your point. I, too, would prefer to "do the least harm" in trying to fix something. The smoke machine would do the trick, but the local mechanic on this island doesn't have one. Autoweek reports that one brand costs $745 list - that's just too much for me.

Most of the time I'm stuck with diagnosing and repairing a problem in the open air. A can of PB Blaster - something that will serve multiple purposes - is a good thing to have with me.

Of course, the best solution is maintaining my car properly. When I bother to check on gaskets, tighten nuts and bolts and do tuneups around oil changes, I tend to have fewer running issues altogether. I only wish I practiced what I preached more often :).

Jeff

[Eric W S]

Eric, I understand your point. I, too, would prefer to "do the least harm" in trying to fix something. The smoke machine would do the trick, but the local mechanic on this island doesn't have one. Autoweek reports that one brand costs $745 list - that's just too much for me.

Most of the time I'm stuck with diagnosing and repairing a problem in the open air. A can of PB Blaster - something that will serve multiple purposes - is a good thing to have with me.

Of course, the best solution is maintaining my car properly. When I bother to check on gaskets, tighten nuts and bolts and do tuneups around oil changes, I tend to have fewer running issues altogether. I only wish I practiced what I preached more often :).

Jeff

Just drive the ECR roverhauled one more often. Problem solved! :thumb-up:

[swaschka]

perfect miss, low power. You're down a cylinder. God bless solihul for developing the variable cylinder technology first! You sure it's a perfect miss? it goes pop...pop...pop...pop. Not pop...pop...poppop...pop? Be real sure you're not moving the same crappy plug or wire around the motor. You can hold a small piece of note paper in front of the exhaust like a flapper valve and watch it suck back to the pipe on the misses. Get real familiar with the sound of that miss and then pull a wire and put it back (yes especially if you just got new wires). Do so for all cylinders of until you've got a wire off and the miss sound is perfectly the same. Then you know which cylinder its related to. If you cannot do this the miss is upstrem from the plug wires. Could be a vacuum leak. Make sure your carb is sealed on the manifold tight. Could be anything honestly, sorry. But if you can get the miss the same with one plug wire off, take that plug wire and replace a second working wire with it. Are you two cylinders down now? No, then try the plug. No, do a compression test. Fails compression test you got a ring or valve problem. But I always suspected the worst and it never was. Soon as I started to check stupid stuff first, I spent less time under the hood.

[scott]

i've a weber 2 brl, 32/36 dgv. go to

http://www.redlineweber.com/html/Tech/32-36_dgev_parts_breakdown.htm

i can't imagine yours doesn't have a mixture screw

[Jeff Aronson]

Just drive the ECR roverhauled one more often. Problem solved! :thumb-up:

Eric, that's the daily lot of the QE I anyway. It's always in use. The engine and drivetrain were not part of the remarkable "Roverhaul." They went back in as they came in; the engine is a Rovers North rebuild from around 1994 and the transmission was a "home rebuild" from about 1998 [most challengingly, by me one week in March].

The delightful challenge of Series Rover ownership is routine maintenance. There's always one more thing to do before it gets cold - and now that it's cold again I'm finally getting around to doing it :).

Jeff

[NC Rover]

If you have another set of points, swap them out and gap them correctly, Make certain you don't have any distributor shaft wobble or you'll never get accurate timing or a smooth idle.

Singing Camel suggests you might have an "inside the cylinder" problem and it's well worth examining.

An easy way - start the car and then, using plastic pliers or insulated handle pliers, remove each spark plug cap. The engine running should degrade until you plug it back in. Try each cylinder in turn. If the engine note does not change, or changes hardly at all, on one cylinder, there's your problem. It could be a simple thing, like a bad plug, or more complex, like a poor valve adjustment [they do need to be adjusted every 15K or so], or worse, a burned valve. A compression test would tell you a lot more.

Another thing to try is to take a can of WD40, PB Blaster, or similar stuff, and spray around the carb body, the throttle shaft into the body of the carb, and when the engine is cold, the intake manifold. You may have a vacuum leak, which would cause similar symptoms. The intake manifold bolts onto the exhaust manifold, and as a unit, to the engine. So the gasket between the block and the manifold is really important and it can fail over time. You might just find that you have loose bolts which are letting air in; the carb is adjusting the constantly shifting amount of air.

The only Weber I'm familiar with is the single barrel so I can't be of great help. In general, Webers are reliable carbs but they can wear at the carb body area. I get about 100,000 miles per carb using the Weber, and find it easy to install and tune.

Good luck!

Jeff

So here is a list of what I've done. Please note, before I did anything, I had the sputtering problem.... it just wasn't constant....it was the "pop pop...popop.....pop"

1.) Fixed the exhaust leaks first by replacing most of the exhaust. I then ordered and replaced the exhaust/intake manifold gasket. Its new and sealed up good with no leaks. The carb has no vaccum leaks either.

2.) Replaced all 4 spark plugs and plug wires. They are gapped correctly. None of the old spark plugs had any sign of oil on them.

3.) Replaced the rotor and cap. No wobble in the rotor at all. I've tried two different kinds of caps.

4.) Adjusted timing by moving dizzy slightly forward and backward until it was running as smooth as possible.

5.) With a warm engine, adjusted all the valves according to the directions on this website (http://www.fourfold.org/LR_FAQ/Series/FAQ.S.tuning_2.25l.html). I went through and adjusted them twice...just to make sure. They are all adjusted properly.

**Now the sputter is consistant rather than spotty like it used to be. Now it is a constant putt putt putt putt putt. There is no backfiring at all. Before when the sputtering was spotty, you would feel lack of power in the low rpms...but once you got up in the higher rpms, it would go away and the engine was smooth with full power. However I would find myself having to keep the choke pulled out just a hair...to keep it running smooth.

I have a friend in town who is going to help me do a compression test but I really don't feel its a problem within the cylinders. I think its something to do with the distributor or the carb. Thanks again for all of the suggestions. I'll update the thread once I find out a little more.

thanks
Nick

[Leslie]

Which kind of Weber 2bbl carb do you have?

Some have mixture screws, but some have to have jets changed to adjust the mixture.

http://www.piercemanifolds.com/carbdetails/carburators.htm

[Momo]

A few things I can think of that haven't been mentioned yet:

Are you still running points? If so are they set correctly and not pitted?
You might consider getting a Pertronix. It will eliminate the wear problems
associated with mechanical points.

Is your vacuum advance functional? Those lines can develop cracks that are hard to detect.

I haven't had a weber 2bbl apart before; are the jets removable? it sounds like you may be bogging due to too much fuel. Especially since you say a little choke smooths it out. Might try a smaller jet.

Have you checked for a fouling plug? Should be obvious especially since you installed new ones.

Worst case scenario: you may be seeing early signs of valve seat wear.

These little problems can drive you crazy because you may make an adjustment to ignition that partially compensates for what is actually a carb problem and vice versa. I work on one system at a time to prevent mental anguish!

[Eric W S]

Buy a vaccuum gauge and google how to use it. It will immediately point you to where you need to devote your attention. IE valve train, piston, timing.

You can also very accurately set you timing with one.

[917601]

Same problem with my 2.6L 6 cyl. However, I do have a fix for it.
It was the points, the distributor shaft has a most unnoticeable "wobble'-axial play- I detected it AFTER removing the points(they were fried-bad condenser?) and looking very closely at the red plastic section that rides on the distributor lobes-it was worn
not flat or "square", almost noticeably "oval at the edge'. In other words- if the surface was put up against a flat edge is was not "flat". It would result in innacurate point gap sttings (.016" for 6 cyl )-if I ever have time or can find a place to rebuild the distributor I will fix it, but for now I have to live with replacing the points every year. A new set of points eliminate the problem until
the shaft wobble takes its toll on the red plastic portion of points.

[917601]

Oh-also-when I first purchased and drove the beast-it popped away relentlessly-I popped the hood at night (pitch black) and watched the plug wires shorting all over the place-looked like christmas.A new set of wires cured the most serious popping.I also cut a 20 inch x2 inch or so piece of metal and laid it on top of the exhaust manifold -used as a heat shield-world of difference keeping the top engine wires, distributor cooler(heat breaks down capacitor and wires quickly)
Be surprised when looking at your engine in total darkness it can reveal what test equip will not,especially on a damp raining night.

[NC Rover]

Which kind of Weber 2bbl carb do you have?

Some have mixture screws, but some have to have jets changed to adjust the mixture.

http://www.piercemanifolds.com/carbdetails/carburators.htm

I have a Weber 32/34 DMTL...I had pierce order me a brand new one as it would have cost $300 for them to completly rebuild mine. The new carb cost me $260 shipped.

[NC Rover]

A few things I can think of that haven't been mentioned yet:

Are you still running points? If so are they set correctly and not pitted?
You might consider getting a Pertronix. It will eliminate the wear problems
associated with mechanical points.

Is your vacuum advance functional? Those lines can develop cracks that are hard to detect.

I haven't had a weber 2bbl apart before; are the jets removable? it sounds like you may be bogging due to too much fuel. Especially since you say a little choke smooths it out. Might try a smaller jet.

Have you checked for a fouling plug? Should be obvious especially since you installed new ones.

Worst case scenario: you may be seeing early signs of valve seat wear.

These little problems can drive you crazy because you may make an adjustment to ignition that partially compensates for what is actually a carb problem and vice versa. I work on one system at a time to prevent mental anguish!

I have a Pertronix. Also have the Jacobs coil ignition. Not sure if my vaccum advance is working. How do I know?

I replaced the vaccum lines. I removed all four brass jets and took them apart...cleaned them thoroughly. It used to run really smooth so I know it does not have to do with changing the jet size. I'm about to replace the fuel lines all together. No plugs are fouled and no oil on the plugs. The engine was rebuilt completly in '94. So not severly old but going on 14 years.

[NC Rover]

Oh-also-when I first purchased and drove the beast-it popped away relentlessly-I popped the hood at night (pitch black) and watched the plug wires shorting all over the place-looked like christmas.A new set of wires cured the most serious popping.I also cut a 20 inch x2 inch or so piece of metal and laid it on top of the exhaust manifold -used as a heat shield-world of difference keeping the top engine wires, distributor cooler(heat breaks down capacitor and wires quickly)
Be surprised when looking at your engine in total darkness it can reveal what test equip will not,especially on a damp raining night.

Theres definitly no arcing. Plug wires are 11mm wires...fairly new. Dizzy cap is new. Maybe I have wobble?

Once I install the new carb, I'm going to replace the dizzy as well. Hopefully that will eliminate the problem. I've done everything else I can think of.

[Oscar]

Had a sticky valve once..... Had similar effects. The vacuum gauge, as mentioned above, told. A can of Marvel Mystery oil for 1000 miles fixed. I do have to disclose that this was on a Jeep.