Lotus Elan

no fuel in carbs

PostPost by: Uboat » Sun Sep 29, 2013 12:49 pm

Hi,
I can't start engine after clutch overhaul, when all pipes were disconnected.
I am pretty sure that the problem is due to no fuel in the carbs (dellorto 40 dhlae). I can see that the fuel pump is working when crank is turned, but it is not enough to pump petrol in pipes up to carbs, not even with starter engaged. How do I fill fuel pipe to supply carbs? (and how do I check fuel level in carbs?)
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PostPost by: robertverhey » Sun Sep 29, 2013 2:20 pm

Perhaps prime the carbs by removing the lids and filling the float chambers manually? Once running, should create enough action by the pump lever to keep up the supply
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PostPost by: AHM » Sun Sep 29, 2013 2:27 pm

I had a similar thing- check that the fuel pipe to the pump is inserted correctly.

otherwise take the plugs out and crank the engine - you should get fuel easily.
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PostPost by: Uboat » Tue Oct 01, 2013 7:19 pm

Thanks,
I removed the plugs and engaged the starter, but I still wont get fuel enough into carbs. Where do I drop fuel into carbs, and to what level?
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PostPost by: robertverhey » Tue Oct 01, 2013 10:32 pm

My excel has dellortos and from memory I had to unscrew the cover and physically lift the covers off to put fuel into the float chambers. Maybe someone else knows how to get fuel in without removing covers. The amount is not crucial, main point is to get enough in there so the accelerator pumps get fed, to give that all important squirt when you operate the throttle.

I should add that in my case even that didn't do the trick, I eventually ended up squirting some neat petrol into each spark plug hole, then quickly replaced the plugs and cranked it, and it thankfully started. I remember when someone suggested that I thought "nah that'll never work"......it did!

Essential to have a fire extinguisher in easy reach when undertaking this process!

You have checked that the fuel lines are clear by blowing through them?
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PostPost by: StressCraxx » Wed Oct 02, 2013 3:22 am

Is it possible hoses to the fuel pump are reversed, or the suction hose for the pump is split? The oxygenated fuels tend to cause rubber fuel lines to deteriorate quickly.

I had a similar problem when my car sat a while. I found the screens at the carbs were plugged, the filter was plugged and the rubber hose on the pump suction had cracked and split under the hose clamp.

If then rubber hose between the tank and the plastic fuel line is cracked, the pump will not pick up fuel either.

Other possibilities:
Debris in tank, clogging pickup tube
Plugged fuel filter
Plugged fuel screens at the carb fittings
Cracked/split plastic fuel line.
Bad fuel pump

Cranking on the starter should fill the carbs via the fuel pump within 30 seconds.
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PostPost by: Uboat » Wed Oct 02, 2013 7:17 pm

OK,
Can I unscrew the bolts and remove float chamber covers easily, without interfering any adjustments?
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PostPost by: AHM » Wed Oct 02, 2013 9:33 pm

Well you can unscrew the tops of the carbs and fill them up , but you still haven't solved the problem. Been there done that!
Do you have a fuel filter? have you changed it?
What type of pump do you have.
Have you been through the system end to end?
Have you taken StressCraxx advice?

You can make your engine run with easy-start if you want to...
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PostPost by: Uboat » Wed Oct 09, 2013 4:59 pm

Well I filled the carbs up, and there was fuel in the combustion chamber, and also spark from plugs. But still no engine running.
So what do I do now? I'm suspecting that I might have mounted the distributor one or two degrees offset when I put it back in the block. Could this be the culprit?
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PostPost by: rgh0 » Wed Oct 09, 2013 11:22 pm

If I cant get an engine to start there are 3 basic things I would check if I had no diagnostic tools.

1. Fuel supply - you seem to have work through this and be convinced you are getting fuel into the engine and that the pump is delivering fuel into the carbs and the carbs delivering fuel into the cylinders
2. Compression - Is the engine compressing the fuel / air mixture in the cylinders? - at a basic level you can tell this from the change in sound of the engine as it turns over with the plugs in versus out or by putting a finger over the spark plug holes as you crank it with the plugs out.
3. Ignition - is the compressed mixture getting a spark at the right time? I would fit new plugs and check timing. if you don't have a timing light just turn the engine over by hand with the plugs out and look for the spark at No1 cylinder plug at around 10 to 12 degrees before Top dead centre on the compression stroke in No1 cylinder, There is a groove on the front pulley and a indicator scale cast into the front cover of the engine. You can feel the compression stroke by putting you finger over the plug hole as the engine is turned by hand ( or by rolling the car with it in gear). Check that all the plug leads go to the right cylinders also and have not been mixed up so the spark comes on the compression stroke for each cylinder

If you do the above and you still cant get any sign of the engine firing you probably need to get some experienced help to have a closer look at what's gone wrong. If the engine itself was not disassembled when the clutch work was done then it is probably something relatively simple that the above checks should discover. .

One additional thought - how long was the car out of action while the clutch work was being done? If it was for a substantial period then the fuel may have lost all its volatile components due to evaporation and be to heavy now to start the car. You may need to drain the fuel out and replace it with fresh fuel including replacing what's in the carbs and fuel lines and pump.


cheers
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PostPost by: rcraven » Thu Oct 10, 2013 9:06 am

I'm not sure from your explanations whether your pump is now properly filling the carburettors or not. I assume you have a mechanical pump. In one post you say they are not getting enough fuel even though the pump is working to some extent. So it seems fuel isn't coming through properly. If you disconnect the pipe to the carburettors does fuel come out of it when you turn the engine over on the starter? If not, you could try putting a rubber hand priming pump in the line to suck fuel through to eliminate any pockets of air.
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PostPost by: Uboat » Thu Oct 10, 2013 5:27 pm

Thanks for help!
I have fresh fuel in carbs, and mechanical pump. As I have filled the carbs, shouldn't I get a couple of strokes even if fuel pipes are stuck? I will check ignition timing...
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PostPost by: richardcox_lotus » Thu Oct 10, 2013 5:50 pm

Daft question - throttle linkages OK ??
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PostPost by: Galwaylotus » Thu Oct 10, 2013 8:49 pm

For static ignition timing I rigged up a light (12v bulb with cables and crocodile clips soldered to the two terminals). Connect one side to the earth side of the coil and the other to a good earth. Rotate the crank until the timing marks line up with 10?BTDC or whatever your spec is. Then rotate the distributor anticlockwise until the bulb lights (just). Clamp the distributor and you're ready to go.
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PostPost by: ricarbo » Fri Oct 11, 2013 8:52 am

You haven't taken the distributor out, by any chance? It's very easy to get the ignition timing 180 degrees out. You usually get the odd misfire if that's the case, but nothing more. So have a look at the cams to make sure both valves are fully closed on number one cylinder at top dead centre and check the rotor arm is pointing at number one plug lead and not number four.
I agree priming the engine with fresh fuel should make it fire up if the timing is even vaguely right, if only for a few seconds. I put, say 5cc in each plug hole, then spin the engine over without the plugs in to blow out excess, then put the plugs in and reconnect. Gets my lawnmower going after the winter lay off! Once started it seems happy enough on last year's fuel, but it won't manage a cold start with it.
regards
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