Bob_Rich Posted September 11 Share Posted September 11 My Lotus seven ( 1969 series 3 with sprint spec crossflow ( by late Steve Parker) ) had stood with very little use over the last year ( tank full with E5) but was kept in the garage. It proved difficult to start so as battery was new and I thought I had some issues with the timing ( but the was not the case) but basically at tick over it was OK checked the tappets and fitted new plugs. changed the fuel filter on the Facet fuel pump. I have had the 40DCOE's cleaned by Chelmsford Weber services and initilally the car started and ran OK which was encouraging however it cut out while out for a blat and although I got it going it became more difficult to start and finally it wouldn't. This is when I looked at the fuel tank and it was VERY badly rusted --so I decided to replace the tank with a new alluminium one. Basically the fuel was badly discoloured and the old steel tank was VERY rusty. The colour of the fuel I took out was very different ( brownish) compared to the new stuff I put in the new tank. Things I have checked to get where I am at now (1) new plugs, (2) sparks at all 4 plugs will jump a 6mm gap of my tester, (3) fuel pump delivers around I litre/minute free flow and stalled pressure around 2psi , what it appears to me is that after endless cranking of the motor there is no sign of life. On removing the plugs they don't appear wet and dont smell of fuel. I removed the top overs of the carbs and checked that the floats and the needle valve would let fuel through OK. The fuel in the carbs float chambers looked decidedly brownish(see picture) so using a syringe I sucked it all out and it does look murky compared to the new stuff. reassembled the carbs and heard the fuel pump rang faster ( refilling the float chambers) tried to start it no go. checked the plugs --to me they dont smell of petrol and they look like they have just come out of the box. So I am looking for a bit of advice / help in what to try next -- I am sure it is do with the carbs --I wish I had known how bad the fuel was before I had the carbs cleaned! thanks in advance if you can offer any help / advise Link to comment Share on other sites More sharing options...
OldAndrewE Posted September 11 Share Posted September 11 The first thought is that there is now some crud somewhere in the carbs that is stopping fuel delivery to the engine. If you operate the throttle do the pump jets spray fuel? 1 Link to comment Share on other sites More sharing options...
Area Representative Andrew Gilbert Posted September 11 Area Representative Share Posted September 11 Blocked jets maybe or a failed pump within the carbs or even a blocked filter where the fuel enters the float chamber? You can have those out easily enough and clean them with liberal amounts of carb cleaner but its unusual to have no fuel getting through. 1 Link to comment Share on other sites More sharing options...
Jonathan Kay Posted September 11 Share Posted September 11 1 Ether spray in the air intake while turning over as a diagnostic test. 2 Fuel filter(s) as above. Plus disconnect at the tank and blow compressed air through backwards. Jonathan 1 Link to comment Share on other sites More sharing options...
Bob_Rich Posted Thursday at 18:52 Author Share Posted Thursday at 18:52 Hi all well I have got the carbs off and when tested on the bench only the 4th pot produces a squirt of petrol when you operate the throttle. So I have got some carb cleaner and going to have a good clean of it following advice from Paul at Chelmsford Weber Services. With the top cover off there is still some dirty fuel in the float chamber. Not to keen on using Ether because up to now no fuel has been coming through, The fuel from the new tank is clear and clean flushed It through with the fuel line off the cabs and into a contained-it was all nice and normal looking . Am going to blow out the jets on the carbs now they are on the bench and thoroughly clean them --again Thank for the advise all most welcome bob Link to comment Share on other sites More sharing options...
anthony1956 Posted Thursday at 19:57 Share Posted Thursday at 19:57 "Car won't start" ooh this gives me the horrors... will have a read now... Link to comment Share on other sites More sharing options...
anthony1956 Posted Thursday at 20:12 Share Posted Thursday at 20:12 (edited) 3 hours ago, Bob_Rich said: Am going to blow out the jets on the carbs now and not just the jets... You have a compressor? Good, I was going to say blast everything. Are the float chambers full when you lift the lids? Are the butterflies swivelling? I LIKE the pump jets test, BUT their not working doesn't mean the main jets aren't. That lousy rotten fuel does look like it has clogged everything. Try blowing in reverse too. Yes I've just been there too (Dellortos - very different problems) - I also use me as the blower (i.e. blow through them yourself so you can feel they are clear - indeed start with that as a test), like the float chambers, blow inwards as I lift the float to check it works correctly. Petrol is an acquired taste 😉 Diagram herewith in case it helps. My money is all 4 main jets/emulsion tubes being blocked - take them to bits (mine not Weber are three pieces each, yours are 4 pieces looks like items 10,11,13,15). Idle circuit first. and don't forget all the little "tubes" inside the body of the carb itself. Quote however it cut out while out for a blat and although I got it going it became more difficult to start and finally it wouldn't Yes this screams fuel blockage(s) big time. Given they have been professionally cleaned should mean they are easy to work on (mine are). Amazon say three left, amazon.co.uk makes a change to be offering ideas instead of receiving them (continuously for several weeks!) Edited Thursday at 22:45 by anthonym Link to comment Share on other sites More sharing options...
Gridgway Posted Thursday at 23:09 Share Posted Thursday at 23:09 It's got to be a carb problem. The old fuel crud has got in there. I know you've said you don't like the idea, but you can isolate the problem by spraying easy start or brake cleaner into the intakes. If the engine runs and stops it's a carb problem. If it doesn't run then it's a spark or timing problem. No need to be precious about it. When we start the BDG (overblown cross flow) in my F2 race car, we take a water bottle, make a hole in the lid and fill it with petrol to have a big squirt down each throttle body to get it going! 1 Link to comment Share on other sites More sharing options...
anthony1956 Posted Friday at 03:14 Share Posted Friday at 03:14 (edited) 16 hours ago, Gridgway said: I know you've said you don't like the idea, I use "Holts Bradex Easy Start" for this (EDIT: looking for air leaks NOT starting the car) , having said that we concur it's crud jammed in there - guilty admission coming up: a few days ago I had flames everywhere (felt like it) when a nearby cloth caught fire having soaked in some of the fluid and I think it was the spark from an open barrel (no filter) set the airborne product on fire which instantly spread to the cloth (a duster). I stamped it out with my crocs. I keep a fire extinguisher a bit more handy now. So that's me being a terrible warning. I still use the Easy Start, just a bit more warily and no nearby anything combustible. Edited Friday at 15:31 by anthonym Link to comment Share on other sites More sharing options...
Jonathan Kay Posted Friday at 21:28 Share Posted Friday at 21:28 I don't have vast experience of this but I'd much rather use diethyl ether than petrol or acetone. Jonathan Link to comment Share on other sites More sharing options...
anthony1956 Posted Friday at 21:35 Share Posted Friday at 21:35 (edited) don't know what Easy Start is..does what it says on the tin tho Edited Friday at 21:36 by anthonym Link to comment Share on other sites More sharing options...
Jonathan Kay Posted Friday at 21:37 Share Posted Friday at 21:37 Bradex Easy Start: https://cdn.aws.toolstation.com/items/coshh/saftey-data-sheet-bradex-easystart-38028.pdf Jonathan Link to comment Share on other sites More sharing options...
anthony1956 Posted Friday at 21:38 Share Posted Friday at 21:38 (edited) DIETHYL ETHER, Hydrocarbons, C6, Isoalkanes, <5% n-Hexane, DI-ISOPROPYL ETHER, ACETONE Same page, contents Section 3.2 "much rather use diethyl ether" So you will like Easy Start... Edited Friday at 21:41 by anthonym Link to comment Share on other sites More sharing options...
Bob_Rich Posted Sunday at 15:24 Author Share Posted Sunday at 15:24 Thanks for all the useful information. Will check ALL the jets and emulsion tubes as well as the starting system. I dont have a compressor. might but I have a mate with one and if I can't clear it I will take a trip to him. Interesting (annoying) week coming Bob Link to comment Share on other sites More sharing options...
anthony1956 Posted Sunday at 18:48 Share Posted Sunday at 18:48 (edited) 3 hours ago, Bob_Rich said: Interesting (annoying) week coming you have my total sympathy - been there for several weeks and compressors are cheap bits of kit and neverendingly useful once you have one - I have an electric one from Aldi, or I did til I broke it (literally) a couple of weeks ago; so bought another also not expensive. This sort of thing (but check details this is just a rough example of amazon.co.uk ) - reason I am pushing a tiny bit is I don't think youll get all that crud out without one at home, having tried blowing through myself, just doesn't cut it. Also good for cleaning grot traps.... Edited Sunday at 18:50 by anthony1956 Link to comment Share on other sites More sharing options...
Gridgway Posted Sunday at 19:29 Share Posted Sunday at 19:29 I can't imagine not having compressed air and tools in my garage if you have space and resources! 1 Link to comment Share on other sites More sharing options...
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