Starting from cold with Dellortos

[jimj]

In the S3 with webers, 2 pumps on the accelerator and the engine fires immediately from cold, unless the car has been stood for more than, say, a week. According to Brian Buckland, the same should be true for Dellortos, no choke just 2 or so pumps. I`m still having problems with the Sprint: Churn, churn, churn, full choke and eventually, reluctantly, it fires up, then it`s fine. Catch it on the accelerator, put the choke away immediately, rev. a bit and it`s runs cleanly. Switch it off, unwarmed, and it fires immediately with no choke.
Determined (almost) to keep the car to factory spec. and not wishing to waste money, but even more determined the car should be perfect, I followed Mark`s advice replacing the whole, everything, ignition system, fitting 123 electronic ignition. I had the carbs. set up by a specialist with a rolling road yet still it`s the same.
I have a theory but what`s yours?
Jim

[jensmartin]

I had the same problem for many years with very reluctant starting from cold (Dellortos) when the car had stood for a week or more. Nowday I fill the carbs with fresh petrol using a bottle with a pipe and it start soooo much easier, everything electrical is standard. I my case i think it was fuel evaporating.

This is what i use, unmounting and filling directly into the fuel line connected to the carbs
http://www.biltema.se/sv/Bil---MC/El/Ba ... -l-351768/

/Jens
Elan +2
Sweden

[richardcox_lotus]

Jim - I'm away from my books at the mo but iirc, dellorto & weber cold starting is not the same. No pumping with Dellortos (oooer missus).

This previous thread may help

http://www.lotuselan.net/forums/lotus-carbs-f40/difficult-cold-starting-dellortos-130-t15934-15.html

[trw99]

Jim, have a look at Alex Black's resto blog/ thread on here. As I recall, his solution was to fit an in line rubber bulb hand primer pump in the boot. Couple of sqeezes and starts much better.

Tim

[alan]

hi Tim,
you have just hit the nail on the head. You are 100% correct.
I have also fitted a bulb in the boot of my Sprint, prime carbs (dellortos), 2 pumps on the accelerater, NO CHOKE. Starts straight away
Just a detail with a +2 the tank is at a high level, so the line is always full upto the pump. With an Elan tank is at low level so the line to pump can empty

[Esprit2]

With a mechanical fuel pump, the engine has to crank a bit to fill the carb's float bowls. With an electric fuel pump, just turn the key and wait a few seconds until you hear the pump slow down, indicating that the bowls are full (ie, that does the same as the squeeze bulb). Then start as usual. The electric pumps make cold starts with either Webers or Dellortos so much easier.

Webers depend more heavily upon the accelerator pump than do Dellortos, and a couple of shots in Webers is more like 3-4 shots in Dellortos. Adjust accordingly.

I have three engines with dual Dellorto DHLAs, and one with a single Weber DCOE. All have electric fuel pumps, and I've not bothered to connect the enrichment devices (chokes) on any of them. I run the pump for a few seconds, give the Weber 3 full strokes of the throttle pedal, and the Dellortos 4 strokes. Then pause for a bit to allow the fuel to evaporate in the manifold (put on 5-point harness, adjust mirror, etc), then crack the throttle about 1/2" at the pedal and hit the starter. The engines usually fire right off. Catch it with your right foot, and keep the engine alive until it settles down to it's own idle.

The only time I miss having the enrichment devices hooked up is on the rare occasion when I might want to start the engine from stone cold, them immediately get out of the car, leaving the engine to run on it's own. In that case it would be nice to be able to use the 'choke' to set a fast idle speed. But for normal start and go operation, the 'choke' is not required.

If you install an electric fuel pump, take the time to install some safety circuitry along with it, like an inertia switch to turn the pump off in the event of an accident.

Regards,
Tim Engel

[mbell]

If you install an electric fuel pump, take the time to install some safety circuitry along with it, like an inertia switch to turn the pump off in the event of an accident.

Also if you install the pump in the engine bay and have electronic ignition you may want to use the same power feed for the pump and electronic ignition. If the inertia switch is trigger it will then cut the fuel supply and spark to the engine. Minimizing chance of fire/engine problems.

[UAB807F]

The Europa has Dellortos and I always started it the same as the Elan with webers, a couple of prods and turn over. In fact I don't even think the choke was connected for the first few years I had it.

Then I read Miles Wilkin's book and he advocates full choke, stating they operate differently from webers and pumping in the same manner will put neat fuel into the air box so any flash-back can cause explosions. That was enough to scare me into wiring up the choke and I've used it ever since.

Brian

(not trusting my memory, I checked the book and it's in the section on "running in" for anyone interested in the details)

[rgh0]

The Europa has Dellortos and I always started it the same as the Elan with webers, a couple of prods and turn over. In fact I don't even think the choke was connected for the first few years I had it.

Then I read Miles Wilkin's book and he advocates full choke, stating they operate differently from webers and pumping in the same manner will put neat fuel into the air box so any flash-back can cause explosions. That was enough to scare me into wiring up the choke and I've used it ever since.

Brian

(not trusting my memory, I checked the book and it's in the section on "running in" for anyone interested in the details)

Some Dellortos I believe had pump jets that squirted straight down into the carb rather than towards the back of the carb and into the engine like other Dellortos and Webers. This may be the source of Miles Wilkins comment that they operate differently as it would be more likely that fuel could drain out the front of the carb and into the airbox with a straight down pump stream.

My Dellorto equipped cars I always start the same as with the Webers but they are tuned a little leaner so tend to struggle a little more when stone cold

cheers
Rohan.

[jimj]

Gentlemen thankyou for your responses. So, yesterday, much churning to start the car and I took it for a run. Last night we went out for the evening and the car fired up immediately, 8 hours later and again 3 hours later to come home. Then, just now, 10 hours later but with lower temperatures, the car needed churning to start. Surely the petrol in the fuel lines doesn`t evaporate or drain away only when it`s dark.
Another thing, having run for 10 seconds, certainly not warmed up, I turned it off and it started immediately.
If, as suggested, you need auxillary pumping, bulb or electricly, why is that not the case with Webers? Do Webers provide additional suction to help the pump pull the fuel through?
Is there anyone with standard set up Dellortos who doesn`t have this problem? I just wonder if it`s coincidence and those with problems like me, maybe have a tiny air leak in the fuel line or a weak pump not working well enough at starter cranking speeds but Ok when the engine is running.
Jim

[UAB807F]

Is there anyone with standard set up Dellortos who doesn`t have this problem?

Jim,

My Elan has an electric pump but the Europa, with Dellortos, has the standard mechanical fuel pump. As mentioned above, I always use full choke now on the Europa and (tempting fate here, ) it usually starts first go. I push the choke in to keep it above 1k revs and it behaves, well, almost like a normal car !

Hot or warm starting I just turn it over and if it doesn't catch immediately I give a pump as it's turning over which seems to sort it out. I do have Pertronix ignition on it now but I don't recall it being significantly worse on CB points.

Rohan - I think you have it on the accelerator jets, what you say makes a lot of sense. After you mentioned it I remember operating the carbs off the manifold and I didn't see the usual long jet of fuel that you get with the webers. They do deliver fuel, but I think you're right in that they have a different injection style.

Brian

[jimj]

All the latest, right here. I`ve just been out in the car this afternoon and it started absolutely immediately. OK it`s a bit warmer than first thing but if the problem is dragging the fuel through, it` s still there after 5 hours, why not after 10?
Jim

[Esprit2]

The float bowls do need to be filled for the carb to work well/ give instant cold starts, and they do drain down/ evaporate over time. An electric fuel pump will normally run for a while when switched on after the car has sat for an extended time (over night or more), and that's a clear indicator that the fuel level was low in the bowl. That happens with both Webers and Dellortos, and is not weird or wrong... they do it. And an engine-driven mechanical pump can't pre-prime the carbs prior to keying the starter... the engine will have to crank for a while.

Depending upon an individual carburetor's new/old condition, or how rich/lean it's tuned, 'one' may cold start better than another. But that's not to condemn either Weber or Dellorto. One guy's Weber might cold-start this time, and another guy's Dellorto the next time. At this age, there's more difference between individual carbs than there is between brands. But as far as brands are concerned...

I have run both Dellortos and Webers for many years, and it's my experience that "In a similar state of tune" (equally rich or lean), Dellortos cold start better than Webers. Just note that Lotus switched to Dellortos later, when emissions were more of an issue, and the factory jetting was typically leaner on the later Dellortos than it was on the earlier Webers. If the Lotus-stock Dellortos start harder than the old Webers you recall, it's because of how Lotus tuned them, not because of a Dellorto deficiency. Enrich the Idle Air Corrector a bit. On an equal playing field (age/ condition/ tune), the Dellortos are superior to Webers in many ways.

Your concern strikes me as being born of too many years driving modern fuel injected cars that don't do that. Your expectations are skewed. No Weber or Dellorto will start like fuel injection.

Regards,
Tim Engel

[69S4]

I don't really have a dog in this fight as my Elan is Stromberg powered with an electric fuel pump but just as a general principle I have seven motorcycles of various ages and types some of which suffer from the same issue of poor cold starting and some which don't. It does seem to be very dependant on carb design; some I can leave months and they start straight away, others just won't go at all without remedial action. In the case of two of the bikes leaving them more than three or four days necessitates draining the float bowl and refilling with fresh fuel to get them to start. One is a Honda with a completely stock carb, the other a bike with a Dellorto carb!

What seems to happen with the poor cold starting ones is that the more volatile components of the fuel somehow seem able to escape. What's left won't then vaporise. Certainly what comes out of the bike float bowls after a week is much darker coloured than fresh fuel. Many people point the finger at modern reformulated fuel but whether there's any substance in this I don't know.

[terryp]

I had two +2's over 4 years and never had a problem starting using the webber method but only once I changed the pump jets to horizontal squirt. They are cheap to buy , to be honest you can't actually buy the vertical ones anymore. I also changed to 35's rather than 50's
I also ran NGK BP6ES.

Terry