Need Help With Carb

[uralrover]

I cannot seem to keep my Carburator running quite the same from week to week. I recently baught another Weber (Don't Laugh) and had to install it to drive cross country in my Series III. Took Most of the drive across the US to get it to run decent (timing was all screwed up). Now that I'm In NY, I cannot seem to get it to run with any consistancy. I'm getting about 13-15 MPG if I drive 45-50 and about 9mpg if I drive 55+. I don't think it's lean but, when it's colder I have to leave it partially choked all the time. I think the trucks running to high RPM at idle (don't have a timing light so can't check). Doesn't smoke excessively, no smell of fuel. I'm a Diesel Mechanic with more time under the hood of Defenders (300TDI's) then under my own Bonnet and need some guidence because I'm just not sure what the heck the Series Petrol is supposed to be like when It's running good?

[yorker]

Where in
NY are you, if you are anywhere near me I could give you a hand.

http://www.lrfaq.org/Series/FAQ.S.tuning_2.25l.html




http://www.lrfaq.org/Series/FAQ.S.carb.weber.html

[scott]

what model weber? i've a 32/36 dgv two barrel. with your travels (defferant elevations) it may be a jetting thing. i found that www.redlineweber.com is a good site for weber info.

[Jeff Aronson]

A new single barrel Weber should operate easily and smoothly. You should not have to pull out the choke to get it to run. Your post is a bit unclear in terms of diagnosing a problem, so I apologize to you if this seems a bit far fetched to you as a mechanic.

1. Many carb problems are actually ignition problems. So just make certain that the points are gapped correctly and are not pitted. You mention that you can't get it timed right. That hints of a distributor shaft wobble. There should be virtually none. If you have wobble then the points are not opening and closing correctly and you'll have poor running. A hint is to look at the underside of the cap. If you have silver or gold-colored bits seemingly sprayed around, then you have a bushing that's failing and the resultant wobble.

2. You might have a vacuum leak. Using PB Blaster or WD-40, run the car and spray around the intake manifold, carb base, carb body top. Any change in idle? If so, you're not going to get it to run well.

3. You might have a bad valve. That will affect idle, will reduce acceleration and power, give you poor gas mileage, etc. A compression test will confirm it. So, too, might the plu wire test. Start the car and remove a plug wire, one at a time. If there's not a significant change in idle when you pull a plug, there's your bad cylinder.

4. The Weber has an idle mixture adjustment screw on the backside of the carb. As you know, turn it in until the car is near stalling, then turn in back out 1 1/2 turns. The idle speed screw is on the right side of the carb.

5. The Weber is subject to carb icing. Every winter, I must run dry gas in my Rover or at near-freezing temperatures, I will be subject to stalling unless I pull out the choke.

6. The Weber is more sensitive to clogging from grit in the gas tank. Remove the 4 screws from the carb body top, remove the throttle linkage to the carb, and lift up the top. The float will come up with it. Look inside the the carb body. If you see a lot of reddish or brown grit, then you will have clogged jets. Unscrew the tiny jets from the bottom and blow them out with carb cleaner. Spray some into the orifices that are exposed. Do the same with any orifice you can see. Remove the mixture screw and do the same. There's a needle on the left side of the carb body, too, so spray cleaner there. There's a 3/4" brass nut underneath the float chamber and a small cylindrical filter resides there. Clean it out also. While you're at it, look at the inline fuel filter and the fuel pump sediment bowl too.

I hope some of these ideas help you. I've had great luck with the Weber's I've put on my Rovers and generally get about 100,000 miles per carb before they wear out.

Jeff

[Tim Smith]

Vacuum leak, vacuum leak, vacuum leak!

Me thinks you have a vacuum leak. If not off the carb (power brakes or vacuum advance) then at the intake manifold.

Have you checked the intake manifold for any cracks? What about the intake manifold gasket?

Don't ask me how I know this.

---

EDIT: Of course Jeff has some great ideas above but I still think it's a vacuum leak.

[Eric W S]

Most local shops have a smoke machine that can easily identify a vacuum leak. Cheap and effective. I paid less than 50 bucks for the service and parts to fix.

Careful with spraying random fluids on your engine. Some might have adverse effects to your pistons. Stick with carb cleaner and you should be ok. Other items may not be as healthy. I almost blew a cylinder using starter fluid on the 4.0. Ignorance sucks.

EwS

[LaneRover]

When driving my 65 109 across country in 1996 I developed a 'squeal' that went away under power. I thought that the alternator was going. One night I almost completely lost power - luckily near a campground.

In the end it was the carb that was becoming loose from the intake manifold. Eventually it wouldn't idle but only would run when I had at least some of my foot in it. With a tiny loosening I got a whistle when I would hit the gas it closed up the gap. Tightened up the carb and everything was fine.

Of course now I had a spare alternator because of course I made assumptions and tried that first!

But my story could help point towards a vacuum leak as just mentioned.

Brent

[uralrover]

I sat down and worked over the problem, checking for Vacuum-leak, (sorry that wasn't it) then ran through the usual problems. After much troubleshooting heres what happened. Solved the ignition short. Adjusted timing and (New) distributer to better smooth out the idle. Checked engine for other signs of excessive wear. Runs better, but; I think I need to adjust tappet clearence. Tested it Monday with a 80+ mile round trip using 4 gallons of Petrol at Hwy Speeds. Seems good. Also quite impressed, didn't use any oil or loose any Anti-freeze, course I didn't let the engine get to hot.
Thanks for all who responded, I used what I could and worked it out.....For now.....