Weber Starting Proplems

dmcsweeney

dmcsweeney

Active Member
Hi all, I converted one of my 3500Ss to a weber 500 carb about 2 years ago, complete with facet solid state pump and filter king pressure regulator. The car has been in the workshop with the last 12 months, only being driven occasionally. I've found it very difficult to start the car if it's left stand for more than a week since fitting the weber. If it is used regularly it starts first attempt, no matter what the weather. The car also drives very well and returns excellent fuel economy. I've found that the choke makes no real difference to starting (and i've checked the linkage/cable is ok). My usual starting procedure is to pump the throttle 5/6 times and crank it over. However, after standing for more than a week, i have to repeat the procedure several times. When it does eventually start it idles roughly and i have to give it very careful throttle to gradually bring the revs up. If i try to rev it coughs and stalls. Once it has run for a few minutes it clears and runs perfectly, and will restart easily. Even after 24 hours it'll start first attempt. The carb was bought second hand, it came on a SD1 vitesse engine and box i bought. I left well enough alone, bolted it on, checked the fuel pressure, turned the key and it fired up. I haven't touched the mix since. The car has been driven about 600 miles since the conversion and once running never misses a beat, no smoke, no hesitation, and as i said good economy. The car always started on the button when it ran SUs, though these broke my heart on a regular basis! Has anyone else suffered these problems. Is there a specially starting procedure with the weber? Any ideas would be welcome.
One more item, when i plumbed the new fuel line i used a coil of micro bore copper 8mm pipe intended for water. I've since heard that copper pipe can split due to vibration if used on a car. What is the correct pipe to use? At the moment it is secured to the car with powder coated "P" clips normally used for FP200 fire alarm cable (these are a snug fit and have a hole for self tappers).
 
It does seem that the Weber excellent carb though it is does seem to have a reputation for hard starting behaviour.
I find with mine that the best starting proceedure is to pump 5 or 6 times leave my foot to the floor and then raise slowly whilst cranking, this give me the best start. The choke seems relativly critical to facilitating the start, I engage the choke fully (on the carb) and it needs to be only partially engaged once started. The car will stall if I try to drive off too soon after the start and it requires to be idled for about 1 minute before I can drive off. Power and fuel economy are excellent a great improvement over the SU's!!.
My car has a problem once hot that it will not restart this is as you can imagine somewhat annoying and may well just be evaporation in the fuel line. I suspect that if I isolate the carb thermally by installing a bakelite or phenolic/resin spacer gasket that I will remove the excess heat from the carb and so eliminate that factor. I suspect I may have leaned off the idle screws a little too far causeing the stalling when not waiting 1 minute before driving off. Haven't had a lot of time to sort these problems yet, I also have an electric fuel pump which is installed in the engine bay next to where the mechanical pump (now removed) used to be.

Graeme
 
Gents,

As you both run a Weber carburettor, and you both speak in glowing terms with regard to fuel economy when compared to the twin SU setup, could I please ask what fuel consumption figures the Weber returns for both city and country running. What did the SU carburettors return?

Thanks in advance,
Ron.
 
Mine doesn't get started very often and in fact was started last night for the first time in about a month.

I have had it to bits :)

Now, I pull the choke out all of the way, and crank it over, not touching the throttle at all.

It fires instantly and runs roughly until I push the choke about half way in, thereafter it runs a little bit lumpy for a minute or so until it starts to warm up.

MPG is based on the first tank of fuel - I drove it from Essex up to Yorkshire, then down to Norfolk and back, and apart from those runs just to work and back, around town, to the shops etc.

I got 24mpg - I expect to get a lot better when it isn't sat ticking over in various garages.
 
I did my conversion in about 2003 and I just wish my grey cells were the same ones now as they were then! :D I dont remeber the exact figures now but 21.3 springs to mind as the round town figure I used to get with the SU's (lots of fuel efficient driving) and that the Weber was around the 24 mark but as I say its all a bit hazy now so dont quote me. I need to get a new Wof and register the car to do some more driving but with work and sevral other cars that I drive much more frequently the Rover has been sadly more neglected that I like :(

Graeme
 
Thanks for your input lads! Ron, i ran the car with SUs for about a year after buying it and had nothing but trouble with the fuel setup. i had fuel leaks from the carbs on several occasions, one carb used to over fuel for no reason, a needle seperated from it's base one day and blocked one carb! I had the carbs apart 6 times! There was an SU electric pump on the inner wing, linked with gas hose to the carbs, and there was a mixture of garden hose and gas pipe linking to the original reserve pipe about half way along the car. The original main line was blanked off with a piece of hose and a bolt! All the original engine bay pipes had been by passed. It was a complete mess, and nearly cost me the car one night when a hose at the back of the block split and started dribbling fuel onto the hot exhaust! I reached under the car and cut the line, ripped it out and managed to catch most of the 30 litres of fuel that was in the tank to prevent it running into the drainage system. My girlfriend followed around with an extinguisher because i was soaked in petrol. All cars over 30 years old in Ireland are exempt from the NCT (MOT) so people tend to bodge sometimes! My gearbox was on the way out so i had bought a job lot of parts (including a rebuilt high ration LT77) which included a weber and facet pump. I spoke to a guy who raced V8s and he told me to ditch everything except the tank, put the pump at the back, 8mm continuous fuel line to the engine bay, filter king at the engine bay, and braid hoses linking the lot up. The system not only has one fuel line (from the reserve output from the tank), the original main line is plugged at the tank, and the return line is gone. The conversion only took about 4 hours in total. The car now cruses at about 2000rpm in 5th at 60mph with the new box. I haven't checked the economy but at a guess i'd say around 25/26mpg on a run. The 5 speed conversion also means i can drive around town at 30mph in 5th and enjoy a lovely burble from the exhaust! Performance is greatly improved, much more torque. I find it much quicker than my SU equipped cars. I can also drive without a fire extinguisher on my lap now! Although i'm considering fitting a plumbed system as extra insurance. Just on Graemes response, i did suffer the same problem once while stuck in traffic for an hour, but not apart from that. The only other thing i have noticed is noticeable induction roar under heavy acceleration. One important thing to mention about original irish cars (most here are imported from the uk) is while many were abused mechanically, structural boby work lasts much better due to the fact that salt isn't used on the roads in the winter. Although my car was bodged there was not one bit of rust or welding visable on the base unit, although it looked like a dog on the surface when i bought it!
 
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