datsun-roadsters
[Top] [All Lists]

Re: Carb Float Chamber Probs....

To: datsun-roadsters@Autox.Team.Net, DemonTSi@aol.com
Subject: Re: Carb Float Chamber Probs....
From: Fred_Katz@ci.sf.ca.us
Date: Mon, 4 Jan 1999 18:46:58 -0800
Van,

1) it happens to only one carb and not both, so it probably wouldn't be the 
fuel pump (assuming it is stock). Normally, when the fuel pump "senses" a 
high pressure on the out-port it causes the diaphram to stop pumping fuel. 
As long as the pressure is low enough to not overcome a spring against the 
diaphram, it will keep sending fuel to the carbs. A high pressure situation 
is where the fuel bowl needle closes the input port at the top of the fuel 
bowl. A fuel pump problem (too-high pressure) would cause both carbs to 
overflow, if both carbs are similarly adjusted.

2) even when you press up on the lever, it dribbles fuel. Do you mean the 
brass tang lever that the float presses against? Pressing up on it might 
alter the adjustment, and throw things off by requiring more fuel in the 
fuel bowl than can be handled, causing an overflow. Reset the bend 
according to specs. For a 2000 SU, I think that's around 9/16-inch or 14+mm 
from the cover to the lever bend. Then use a needle-nose pliers to remove 
the clip holding the needle and spring in place, and remove them. Check the 
needle and seat to make sure they aren't damaged. If they look good, and 
the brass tang is adjusted correctly, and the float doesn't have a hole in 
it, all should work correctly.

Check your float to make sure it doesn't have a hole in it. If it does, it will 
absorb fuel and won't have enough bouyancy to press up on the brass float lever.
And use a ruler to make sure the lever is adjusted correctly. Invert the fuel 
bowl cover, and measure from the cover to the top of the tang bend.

Hope this helps.

Fred - So.SF

___________________________ Reply Separator ______________________________
> Subject: Carb Float Chamber Probs....
> Author:  DemonTSi@aol.com
> Date:    1/4/99 8:05 PM
>
> Thanks to keith williams (keith0alan) I was able to replace my worn and torn
> float chamber gaskets with clean, new ones. Screwed the tops back on and no
> more fuel squirting out the gap. BUT, as murphy's law dictates, a new problem
> arose. Fuel started spurting out the overflow of the second again. Fast
> forward to the problem: when the spring-loaded needle is shut, fuel flow
> should halt, but mine seems to be dribbling fuel out even when I press up on
> the lever. I can't see any foreign particles in there, so is there another
> potential problem? I'm going to go ahead and see how much of it I can safely
> dismantle tonite (it'll be a fun learning experience too, as I also just
> recently broke down and am polishing my piaggio ciao's carb :)  but I'd also
> appreciate any advice on what to look for...or maybe pointers regarding what
> the problem might be.
>
> Van

<Prev in Thread] Current Thread [Next in Thread>