Float emptying

[sphinX]

Hi guys, When in 3rd or 4th or even 5th after 6k rpm the car suddenly leans off. I'm guess this is due to the float emptying. What could be a solution to this? I have no idea what was done to the carb before hand, but it was running fine and recently starting to lean out.

Looked at the wizards previous convos and he said to someone.

"You need to keep the fuel level in the carburettor up, so either you need to increase the size of the needle jet (try 2mm or more) but sometimes this can cause running problems. Or, use an injector to fire fuel into the base of the carburettor. You can replace the 12mm nut at the bottom with a fuel pipe, and inject extra fuel into this hole when you are on boost. This should keep the fuel level in the carburettor nice and high."

How is this done? And would this be a complete fix?!

[raj]

Speak to ave, im sure he's tee'd his fuel line so that one part of it goes directly to the fuel bowl. im think he drilled and tapped a fitting to the side of the bowl and went from there..! im sure he'll make more sence of it than me.

[5teve L]

Get it apart & check the jet sizes so you know what you are dealing with from the off rather than guessing.
Then think about a larger needle, I doubt you will need to mess with an injector set up unless you are going to try to run well over 220bhp or 23/24psi manifold.
You can pick up needle jets from a few places 2mm standard, if you do a search you shall find

I take it you have an uprated pump as well....
You could also check fuel pressure to the carb is 4 psi above boost.. but it may just be the hot weather evaporates the fuel faster with extra heat under the bonnet ??

[Maka]

http://cgi.ebay.co.uk/Schwimmernadel...3A1%7C294%3A30

i do believe thats the right fitment (2mm needle)
i brought one of these and it works, took a few days to arrive.

[sphinX]

Cheers guys

[Alastair]

Hi all, I know this is a bit of a hi-Jack but the title fits. I am suffering similar issues with my 1.7 mm needle vv, so I ordered a 2.0mm one from eBay at the link above in this thread and it doesn't want to seal at higher boost, basically the carb goes mega rich after a couple of seconds at WOT - 9 AFR. I've tried drilling out a 1.7 with the same problems experienced, so have I been unlucky abd should try another 2mm vv or should I modify the float to compensate?

Also I am a tad rich on part throttle (120 main, 1.0 air corrector and first, 1.2 2nd and 25mm venturi) up to 12.5, what should I consider to lean it out a bit more on part throttle, as I am still a bit lean at WOT too (13 AFR)...? any advice appreciated!

[Maka]

Hi all, I know this is a bit of a hi-Jack but the title fits. I am suffering similar issues with my 1.7 mm needle vv, so I ordered a 2.0mm one from eBay at the link above in this thread and it doesn't want to seal at higher boost, basically the carb goes mega rich after a couple of seconds at WOT - 9 AFR. I've tried drilling out a 1.7 with the same problems experienced, so have I been unlucky abd should try another 2mm vv or should I modify the float to compensate?

Also I am a tad rich on part throttle (120 main, 1.0 air corrector and first, 1.2 2nd and 25mm venturi) up to 12.5, what should I consider to lean it out a bit more on part throttle, as I am still a bit lean at WOT too (13 AFR)...? any advice appreciated!

leave the main and up the 2nd to 1.4mm for wot.
as for leaning out on part throttle, im not sure as i have a rich part throttle.

[Alastair]

leave the main and up the 2nd to 1.4mm for wot.
as for leaning out on part throttle, im not sure as i have a rich part throttle.

Maka, i think your right with 2nd stage, but to lean it out accross the lower range can i increase the size of the air corrector so say 1.1 (or should i go the other way 0.9 i cant remember!)?

[Alastair]

Just re-read Ian S's 32 DIS thread https://www.rtoc.org/boards/showthread.php?t=4734 (for the 400th time) and found a very good few lines from Scoff which kind of answers my earlier question. So i need to tweak down my fuel pressure and lean out my first stage by reducing the jet size more and try reseating the 2mm vv... good old articles section..!

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The 2mm needle valve does a good enough job of keeping the bowl full. Aparantly the 2mm valve doesn't work well on some cars, causing stalls during gearchanges or after hard pulls, possibly down to the accuracy of the home-drilling causing them not to seal properly, but worked fine for me. With an adjustable fuel pressure regulator I think maybe it doesn't take alot of extra pressure to force the needle open when it should be shut.
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