Lotus Elan

MASSIVE spitting....... where am I going wrong?..........

PostPost by: berni29 » Mon Jan 29, 2007 4:53 am

Hello again.

Now that I have the ignition working, I am getting major spitting out of No4 carb, light spitting out of no3 and none from Nos 1 & 2. Not with the engine iding, but at constant revs. Less on blipping but still there. I have seen flames in the throat of No4 on occasion.

It seems strange that I only get spitting out of the back carb.

My colourtune is telling me that the carbs are rich (will not weaken off to a blue flame). On pulling after idle the plugs are very sooty. The car will idle fairly well, and will do so with much more advance than I thought possible. I know because I started it that way after reversing the rotor arm.

Does anyone have a list of jet sizes that works in the real world with 30mm chokes? Probably arrived at after much experementation!

I have nearly all the bits to put fuel injection on, and believe me I am getting tempted! It would be nice to get the car driveable for a while first though.

Thanks in advance for any suggestions.

Berni
Racing green +2s with green tints. See it at:

www.searchsmart.co.uk/lotus
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PostPost by: berni29 » Mon Jan 29, 2007 6:28 am

Hi There

I have read back through my previous posts and found that I asked the same question in July of last year.

http://www.lotuselan.net/forums/viewtopic.php?t=13248

I need to work through the suggestions again, although since then I have had the head off so I know that there is nothing blocking the exhaust and that the valves cams etc are OK.

I have just got a copy of Keiths white paper from sidedraft central (as per Rohans suggestion) and will be following it to the letter.

Many thanks... Berni
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PostPost by: alaric » Mon Jan 29, 2007 7:56 pm

Hi.

I bought a 4 column manometer from carbtune, and a book that explained the carb setup approach:

carbtune thread:
http://www.lotuselan.net/forums/viewtop ... ght=#58120

weber/dellorto thread:
http://www.lotuselan.net/forums/viewtop ... ght=#59188

I ordered them both from ebay and they helped me sort out the carbs really quickly. I reckon that unless you sort them out methodically you'll never get the tuning right. The book explains how to get the settings almost right before you start the engine; my dellortos had been rebuilt but they hadn't been tuned. By the time I'd finished adjusting them I could hear the difference when adjusting any of the mixture screws, whereas at the start the tickover was very lumpy and mixture setting didn't seem to make much difference. So, my advice is to run through the procedure in the book first, before changing any components; see if you can get the mixture and balance right first.

Hope this helps.

Sean.
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