And the next problem is ........

[Hamish Coutts]

And the next problem is ?..

Having just finished changing over to a Brise starter and replaced the worn out Lumenition with an Aldon, I took the car out for a test run and it was going nicely. All was fine in the world and the sun shone from the exhaust pipe. That was a few days ago.

The other evening her indoors & I decide to go for a run. You know, nice evening, car going well. We get ? a mile and the damned thing starts firing on 2 cylinders + strong smell of petrol . Turn power off at master switch, exit car with extinguisher to hand, open bonnet. Fuel is dripping from airbox. Remove cover and back carb is the culprit.
Thinking it?s a stuck needle valve I give the float chamber a rattle with a spanner and mop up any petrol lying around. Turn on fuel pump (facet red top) - no more drips - fine. Decide to take car back home & go to pub. By the time we get home (only a couple of minutes) the car is back on 2 cylinders and dripping petrol again.
I stripped the carbs (Dells) and removed much crud from float chambers and throttle pumps, changed most of the little rubber seals, pump diaphragms and the needle valves (I was going to overhaul the carbs anyway). I reset the float levels as per manual (thanks for pointing the section out, Rohan) and put the carbs back on.
Car starts OK and the tickover settles down to and even 750 revs. However, a few minutes later fuel starts dripping from back carb again, the tickover gets rough and then stops.

Fuel is actually dripping from the main venturi in both throats. Mmmm. Float levels?
They check OK but I increase the gap from 15mm to 16mm anyway ? just in case. There?s no more serious dripping but after running the engine for a minute or so at 2,000+ revs the throats of the back carb seem a lot wetter than the ones in the front carb (they seem almost dry). Also it looks like there is a petrol drip about to form on the venturi again.

I think fuel pressure is OK. It?s regulated by a filter king that?s only 9 months old and the float levels seem OK. Plus the front carb is behaving itself.
The floats also look OK ? there?s nothing obviously wrong with them but I don?t know how to check them for leaks. I still think it is a float level problem but I don?t want to increase the gap any more. I've seen posts referring to checking the fuel level with float in situ. How do you do this and what should the level be I wonder.

Anybody got any ideas about this? It is most frustrating and it?ll soon be time for firing spanners across the garage floor again!!

[tdafforn]

Still sounds like fuel pressure...
If it is too high then the leak may only come from one carb ( the one the needle valve isn't seating quite optimally in).
Worth checking the pressure regulator, as it is not unheard of for them to malfunction.
Cheers
tim

[rgh0]

Hamish

I would check the actual fuel pressure using a guage and ensure its no more than 2 psi. If its still flooding It sounds like time to follow the manual advice in the event of persistent flooding and replace the float valves with the viton seated type and reset the floats appropriately.

Rohan

[marcfuller]

Regarding setting fuel level-

The in-situ measurement allows float level to be set perfectly and takes into account variations in float buoyancy and fuel.

Get a copy of Keith's DCOE tuning paper, he provides simple instructions and photos on how to use a clear acrylic rod to measure how far the fuel level stays below the passageway that connects the well to the auxiliary venturi.

Keith has the white paper posted at-
http://autos.groups.yahoo.com/group/sid ... l/messages

The white paper link is in message #27

[chrishewett]

Hamish,
I think I have had the same problem. Fuel dripping from the O rings and the engine running like a bag of nails. I have a pro fuel regulator from QED. I was told by Corten Miller that they have had a lot of problems with many pressure regs so they fit there own device and make sure the pressure is right. Mine was set at 1.5 and it seems to have been at about 4. Don't run the engine in this condition as it can quickly be wrecked.
I am in about the same situation as you at the moment and have had to cancel the Hockenheim trip.
Never mind, I have always got the f*****g garden to work on this weekend instead!
Chris

[stuartgb100]

f*****g ?

If it's the garden, then surely it's " forking " ?

Maybe not ..........

Regards,
Stuart.

[Hamish Coutts]

Chris,

I take it the 'little something' you were going to get for the weekend won't be from the barbers but from the garden centre - a packet of grass seed .

Bummer about Hockenheim, though.

Hamish.

[cliveyboy]

If you think it is fuel pressure to high.
I have just bought a low pressure fuel pump from "Eurocarb" the Dellorto specialists. It has a pressure of 2psi so does away with the need for a regulator.
I have not had time to fit it yet but it seems a clever piece of kit as unlike conventional pumps it is designed to suck fuel as well as push so it can be fitted in the engine bay.

Clive

[chrishewett]

Clive,
I wish I had known about that.....- but maybe 2psi is too much?
Chris

[Hamish Coutts]

Chris,

When I got the filter king, I'm sure the pressure was set at 2psi by the factory. Since then I've reduced the pressure by 1 full turn of the adjusting screw. There's still a drip from the back carb - only just.

I tested the flow through the regulator and it filled a jam jar in a few seconds. Seems far too high! Will try & beg/borrow a pressure gauge to see what 's happening.

Enjoy your gardening. That's what I'll probably be doing as well.

Hamish.

[marcfuller]

"tested the flow through the [pressure] regulator and it filled a jam jar"

Please realize that flow (or volume) has very little to do pressure in your situation.

[ppnelan]

I stripped the carbs (Dells) and removed much crud from float chambers and throttle pumps..

If there's this much dirt IN the carb then there's probably more being pumped in every time it runs. The overflowing carb indicates that the needle valve isn't closing. ANY dirt in the system can jam open even a new needle valve. I suggest you flush through ALL the pipes & pump, fit a filter, and clean out the carb & needle valve before trying it again.

And keep that fir extinguisher handy

Matthew

[thor]

On mine I haven't got an auxiliary petrol filter, Where should I fit this in the engine compartment, before or after the fuel pump? (standard pump with glass top).

Also: The PO had the car for 26years, rebuilt the engine twice at a TC specialist, and is an engineer. There are however two things in the fuel system I'm worried about:
The fuel pipe between the Webers is a shiny black plastic pipe which I haven't seen before, it looks almost like it's been shrink-fitted. But no hose clips. The pipe coming from the firewall into the pump is CLEAR, and looks like it's wrapped with something where it goes onto the pump, and I can't see a hose clip here either. This seems to be sweating a wee bit.

WHAT should I do, and is this a cause for concern?

I'll take a pic at the weekend and post it.

[Hamish Coutts]

I fitted a fuel filter between the tank and the pump (all of this is in the boot). It's one of these glass thingies that can be taken apart and cleaned. I have also fitted a new fuel line right up to the filter king in the engine compartment.

Chris - to answer your question about fuel pressure. I called Eurocarb this morning and explained the problem. They were very helpful and gave me the following information:
- pressure, pressure, pressure. Check the pressure. I got a test gauge from them for ?13.50. The pressure should be 2 to 2.5 psi. The gauge fits into the filter king for testing. It is not a permanent feature.
- if the regulator can't be adjusted down to 2psi it is faulty.
- it's not worth doing anything until I've checked the pressure.
- if only 1 carb is leaking, swap the float chamber lids to see if the problem moves. If it does, it's probably either needle valve or float. If it doesn't ?
- to check the floats put them in petrol side by side. They should float at the same level. If they don't then one is probably absorbing petrol.
- if you need to order a new float use the number on the top of the float to order. There are 2 types of float and the ones installed in your carbs should both be the same type.

The guy was surprised to hear that I thought filter kings could be unreliable. (I mentioned feedback from posts on here). They have been selling them for years and only ever got one back. (that was because the owner damaged it)

The low pressure fuel pump they sell is about ?45 but they said to stick with the facet red top and regulator I have fitted as I wouldn't gain much by changing.

Hamish.

[Rob_LaMoreaux]

When I put my car back together I bought new float valves for the stromberg carbs since I did not trust something that had sat for 20 years.

Later I was driving and it started running rough. I stopped and found fuel dripping from one of the carbs. I took it apart and found that the float valve was sticking open, so I stuck the original in to get me home. In another incident I found the other float valve sticking closed. A guy at a local shop had some NOS float valves sitting at home they I bought and they work much better.

I could tell it was the float valve sticking open because I could blow into the fuel inlet (mouth pressure) and with the valve pressed shut I still had air coming out. Also the bad float valves felt sticky when I moved them up and down with my finger.

Rob