Weber starting

[miked]

My friend has a problem with starting his car (S4) if it has been left for more than 4 or 5 days. It runs fine, starts ok after (up to) a couple of days. Is it correct to think the fuel from the carbs evaporates so the initial cranks are just getting the bowls full. Or am wrong. He is toying with fitting a an electric pump etc. Sound a waste of time and money as the car runs well.

I have the Stomberg set up on my Elan, and after about week I have to crank until fuel is delivered (i think) as I will only get a fire and start after 20 seconds period. I have always put it down to evapouration??? and having to wait for fuel.

If evapouration is his problem, is he better not doing the throttle pump thing and cranking to bring fuel and then stopping and doing the pump.

How about fuel run back down the pipe, is this possible with a dodgey lift pump without is showing a fuel leak as well.
Any help/advice appreciated.

Mike

[Matt7c]

Mike, I can't diagnose your friend's problem (there are others who know this stuff better than me), but I can tell you that I installed an electric fuel pump in the boot inexpensively and that it works very well. Whenever I come to the car after a few days, as soon as I turn the key, I can hear the electric pump putting more fuel into the bowls before I crank. So an electric fuel pump may possibly remove the symptoms, if the cause of his trouble is fuel loss from the bowls. You can get blanking plates for the engine block if he removes the mech fuel pump, although before I got that, I just put the pump back in place with the arm removed.

[berni29]

Hi

My plus 2 needs a bit of a crank if it has been left for a week or so. I do not remember that being the case with my previous plus 2 though.

Berni

[type26owner]

You can inspect the fuel level in the carbie in about 30 seconds. Remove an inspection cover and an emulsion tube. You'll be able to see the fuel level in the 'well'. It should be 25mm below the top of the carb body.

Sounds more like a loss of compression due to the oil draining off the piston rings after a few days. Synthetic oil might help because it does not drain away until the surface is dry like dino oil does. Also any oil that has been diluted and thinned by fuel and water vapor by leaving it in the pan too long will do this. A compression check would tell if that's the cause or not.

Replace the Lucas starter with a modern one that cranks the engine over faster.

[twincamman]

my 7 tc has the same start problem when idle for a few days --the gas simply leaks down below the needle and valve in the float bowl but it has no problem starting when the float bowls are filled via the mechanical pump after some starter revolution -----the ?lan tc has an electric fuel pump and starts immediately after a week or so parked -----[synthetic oil is just that ---synthetic --ain't nuthin better for an old car than Dino oil ] ---ed

[miked]

Guys thanks for replies. Food for thought!

I will get him to check the levels, I was going to pull the lids but as Keith says we can lift an E tube.

Re: elec' pump, I was digging and found a nice article in an old Classic Ford (2003) mag showing an install with the facet, filter king fuel pressure regulator and an inertia switch etc.

Keith, do you know what the pump pressure should be for the twin 40's so as not to cause a problem to the float valves with too much pressure?

re oil, what does Dino mean about about old oil. Is it as in T.REX type dino's.

Thanks Mike

[twincamman]

just that ---oil from the pre Jurassic period [ close to my birthday] ash oil composed of forgotten vegetation and things long dead pumped out of the ground -- --------- the ?lan has a high pressure electric fuel pump ---[ with no pressure regulator ] to avoid fuel starvation at race speed---but is no problem on the street or at highway speeds or conditions involved with every day driving ed

[type26owner]

The stock mechanical pump puts out about 5-6psi. The float bowl needle will handle this pressure without a problem normally. If you add a Filter King then set the pressure to 3psi and no less and change the needle valve from the stock 1.75mm to a 2.0mm one. Otherwise the float level will drop too much at full song accelerating down a long straightaway.

There is no way for any fuel to trickle back out of the float bowl. I suppose it could evaporate if it had a high enough Reid vapor pressure rating. No way is that a problem here in California anymore.

re oil, what does Dino mean about about old oil. Is it as in T.REX type dino's.

Yup and we've reached peak oil already so enjoy your cars now before we can't afford it anymore in a few more years.

[twincamman]

ok wrong hole [an old sailor joke] -- the fuel leaks from the bowl via the fuel passage and slow running port which lowers the level in the bowl and opens the needle valve as the float sinks constantly lowering the required level to start the motor----- thus the Level must be raised to provide a suitable levels to start the car by cranking the starter and rotating the idle cam and causing a pumping action ---ed ---- and like the song says 'it never rains in southern California '

[type26owner]

Hey Ed,
You'll appreciate this quote from the original Lotus Workshop Manual that came with my car. "There are no mysteries in tuning Weber carburettors. It is not difficult but it cannot be done quickly and a good deal of patience is needed." Yeah, like the rest of your lifetime!

They had Newspeak wayback then too?

[twincamman]

I always liked the Fiat Manual-----If the car stops-- locate the problem --rectify it and continue on your way ------whatsa the problem?--ed

[twincamman]

Kieth----reflecting on the Webber carbs system I realized the whole auto industry is based on 1890 technology---- gas powered motors fed by injection which is really a souped up carb---we really need to get on with electric or hydrogen powered vehicles ----methane would be cheap --just feed granddad some more prunes before a fill up ------propane could be used but a rear ender would let the whole block know something bad had just occurred involving some rocket fuel ---I look forward to the day the Arabs have nothing to eat but their oil and my that lotus goes on forever ed

[69S4]

many years ago I read in a Lambretta scooter manual when referrring to push starting " continue to push until engine starts or you reach your destination"

[twincamman]

69 s4 ----:lol: the best yet ---ed

[miked]

Guys thanks for carb info'. Will have ago with my friend at sorting it.

Mike