Lotus Elan

Weber - gas coming out of 1 throat

PostPost by: SENC » Mon Oct 28, 2024 10:49 pm

Excellent!
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PostPost by: Quart Meg Miles » Tue Oct 29, 2024 5:58 pm

What a saga which I've only just come across, having serious problem with my wife's Xedos' ECU.

I guess your Weber supplier owes you a refund for faulty goods, it doesn't inspire confidence and I wonder how many other people are having this needle problem simply because of the time they've had the Webers; I fitted my 151s in 1999 and they've seen 80,000 miles so I think I'll take a look at my needle valves. I'll do it this winter when I take the head off to replace my Cometic head gasket which has a water leak on No. 3 cylinder, fortunately only into the head and not reaching the oil, causing misfiring straight after starting and low compression. The damage may be where it has to be cut away around the oil drainage rubber tube.

Your oil leaks on 1 and 4 were obvious from the photo of the plugs in you first post. The real irony is that you changed the Stromberg head for a Weber one. Yet Miles Wilkins published his personal experience of the Stromberg producing more power with his late series SE cams than most Big-Valve Sprints; the factory checked out his 0-60 times after it was run-in and they were the fastest they'd ever seen.
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PostPost by: steve lyle » Wed Oct 30, 2024 12:56 am

Quart Meg Miles wrote:What a saga which I've only just come across, having serious problem with my wife's Xedos' ECU.

I guess your Weber supplier owes you a refund for faulty goods, it doesn't inspire confidence and I wonder how many other people are having this needle problem simply because of the time they've had the Webers; I fitted my 151s in 1999 and they've seen 80,000 miles so I think I'll take a look at my needle valves. I'll do it this winter when I take the head off to replace my Cometic head gasket which has a water leak on No. 3 cylinder, fortunately only into the head and not reaching the oil, causing misfiring straight after starting and low compression. The damage may be where it has to be cut away around the oil drainage rubber tube.

Your oil leaks on 1 and 4 were obvious from the photo of the plugs in you first post. The real irony is that you changed the Stromberg head for a Weber one. Yet Miles Wilkins published his personal experience of the Stromberg producing more power with his late series SE cams than most Big-Valve Sprints; the factory checked out his 0-60 times after it was run-in and they were the fastest they'd ever seen.



Yes, one irony is that this would have cost me a lot less if I had just bought another set of Webers and trashed the original set. Assuming the 2nd set had good parts, which I guess is quite the assumption.

What oil leak? There was a coolant leak, solved with surfacing the head. There was an external oil leak, solved by welding up the crack in the front cover. I'm not aware of any internal oil leaks, but as you say, it's been a long saga and I'm probably getting forgetful. I think what you saw in the first picture was the way over rich state given the needles.

You did make me go back and read my first post - the real irony is that Red Line asked me to check the needles - which I did, but I just couldn't tell they were bad, since I had nothing to compare them to and the fault was pretty subtle.

Yes, I know the Strombergs were fine - I was more doing this more out of 'why not' than 'why'. I do have more power now, but that's because I've got a fresh lower end and much better compression.
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PostPost by: Quart Meg Miles » Wed Oct 30, 2024 12:55 pm

"What oil leak?" Your post June 18:

"Maybe the bigger issue is the oil on top of the pistons and seeping in front of #1 and back of #4" suggests an oil leak somewhere. No sweat, just my reading of your report

BTW, I've only used a chain hoist to fit the head since having to juggle with the recently fitted 4-2-1 exhaust while fitting it. Actually that was back in 2016 when I was only 73 and weighed 130 lb but I still just lift the head off, or did two years ago.
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PostPost by: pcarew » Sat Nov 09, 2024 2:31 am

Hello Steve,
I have a 67 Elan and seem to have a fuel/carb flooding problem too.

How did you get on with the HF Fuel Pressure test?

I'm thinking that I need to get my fuel pressure tested. A while ago a local garage (not Lotus specalty, but specializes in other British classic cars) replaced the mech. fuel pump. Not sure what they replaced it with.

I'd been having some issues of the car stalling out when idling on an incline. All of the ignition system has been check/replaced and so I was onto the Webers.

I took the tops off and found that the needle valves were too big (2.00 instead of 1.75) and the float clearance had been set at a whopping 16mm instead of the spec.d 8.5mm.

Feeling pleased with myself for thinking that I'd found a root cause, I reset the floats to 8.5mm

As soon as I started the car up, I had fuel pouring (not a drop, but a flood!) out of the air intake. After immediately shutting down the engine ( and counting my lucky stars for no fire), I ordered new 1.75 needle valves.

I'm wondering if the previous shop had set the float level so low in order to resolve a flooding problem.
It could be a worn / stuck needle valve, too big a needle valve or too much pressure.

As I mentioned, new 1.75 needle valves on order, but I was wondering how you went about checking the fuel pressure in your car?

Paul.
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PostPost by: h20hamelan » Sat Nov 09, 2024 3:14 am

You do need fuel pressure tested, or simply a gauge and regulator up front by your carbs.
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PostPost by: pcarew » Sat Nov 09, 2024 3:51 am

I'd rather not add a new piece of equip. (plumbed in pressure gauge) permanently.
I would just like to know what the normal pressure my fuel [pump is putting out and then take action (pressure regulator or replace pump) if warranted.
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PostPost by: steve lyle » Sat Nov 09, 2024 6:48 am

pcarew wrote:I'd rather not add a new piece of equip. (plumbed in pressure gauge) permanently.
I would just like to know what the normal pressure my fuel [pump is putting out and then take action (pressure regulator or replace pump) if warranted.
current


Paul,

I got a low pressure gauge from Amazon. The one I got was 0-5 psi, but 0-10 or 15 would do. Just don't get a 0-100. With the carbs off, I plumbed it into the output of the fuel pump, removed the plugs and cranked the engine, and got something well over 7 psi. The book says Webers don't like anything over 2.5 psi or so. The next step was to order a fuel pressure regulator from DBE. The std one they sell is a Holley and has 2 outlets - one got plumbed to my gauge, the other to the carbs. I installed the regulator on the front wall of the passenger footwell. I ran the engine and adjusted the regulator down to 2.25 or so, then removed the gauge and put a plug on that second outlet. That's how I'm running now.

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Steve
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PostPost by: pcarew » Sat Nov 09, 2024 8:25 am

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PostPost by: alanr » Sat Nov 09, 2024 8:54 am

If the original mechanical glass bowl fuel pump has been replaced by the all metal body type (no glass bowl) type then they are notorious for delivering a much higher incorrect fuel pressure and will certainly cause your Weber carburettors to flood.

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PostPost by: pcarew » Sat Nov 09, 2024 11:31 am

Hello Alan, tbanks for the insight. Yes the mech. pump was replaced with a ' non glass bowl' type. It certainly sounds like I need to start out by checking the fuel pressure.

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PostPost by: pharriso » Sat Nov 09, 2024 12:19 pm

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PostPost by: alanr » Sat Nov 09, 2024 1:16 pm

pcarew wrote:Hello Alan, tbanks for the insight. Yes the mech. pump was replaced with a ' non glass bowl' type. It certainly sounds like I need to start out by checking the fuel pressure.

Paul


You need to go back to whoever fitted that fuel pump and get them to remove it. It is not suitable for use with Weber carbs.
The original fuel pump can be easily overhauled if necessary and will deliver the correct pressure. Overhaul kits are freely available and are simple to do.
There is no need for having a fuel regulator whatsoever fitted to your car at all if you have the correct and original mechanical fuel pump fitted.

Alan.
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PostPost by: SENC » Sat Nov 09, 2024 1:42 pm

Check your fuel level from above, too, to make sure the float height was an error. It sounds far enough off not to be the case, but I'd double-check to make sure. Brass vs plastic floats also have different height settings.

To check from above, once you get it all back together take one emulsion tube out of each. As the carbs are just relying on idle jets, you should notice no difference at idle without emulsion tube's and their main jets). After running briefly to allow fuel level to stabilize in the carbs, shut off and look down the carb throats with a light for obvious drips - location will suggest whether any observed drips are coming from the main or the acc pumps. Remove carb tops and peer down the chamber for the emulsion tube in each carb with a light. You should be able to see the hole to the venturi on the wall of the chamber. Generally, fuel level any higher than 1mm below that hole will cause flooding - and if you noted dripping in the throats and this fuel level observation is right at the hole, you can bet your floats are too high.
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PostPost by: steve lyle » Sat Nov 09, 2024 5:40 pm

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