petrol disappears !

Jul 14, 2003 5 Replies

After my pinto /weber carb'd Hawke has been standing for a few days, it takes an age to start up due to petrol having presumably drained back into the lines / tank.



I know this is a reasonably common prob, but have not found an easy, relatively cheap solution. I have one of those plastic in-line filters near the carb, and it appears almost or completely empty after a week or so. All fuel lines are new, filter is new, no leaks anywhere, so is it draining back, or evaporating? I have considered a couple of ideas, such as a one way (non-return) valve just in front of the filter, also even considered an electric pump rather than mechanical. All that ctranking for ages is doin my battery in, and sounds naff anyway!! Any ideas folks?



PS if ohm's law states I=V/R, how come a 12v battery can supply more than



12 amps when shorted?? 12/0 (assuming no internal resistance)=12.


Not quite.

12v/1 ohm -> 12 A 12/0.1 ohm ->120 A 12v/0 ohms = infinite current

Typically a lead acid car battery might have an internal resistance of about 15-20mOhm (0.015-0.02 Ohm), so if it is shorted, a current of approx.

600-800A will flow.

Andy

Fit a one way valve in your fuel line.

Euh no: 12/1 = 12, 12/0.1 = 120. 12 /0.01 = 1200

12/0 infinite... Tom De Moro

Oops, Andy was before me...

On a small battery shorting will make some noise and heat, on a big battery (as in a truck) the batterie will explode.

Regards,

Tom

Because 12/0 doesnt equal 12 .... tap it into a calculator and see You could in theory get an infinitely high short circuit current, however there is always resistance

12 volts and all that....

Oops, yes of course I got my maths wrong ! Obvious when I look at it now.TY for all replies, sarcastic and otherwise! Think I will try Richard's idea of an electric pump, but wondered about its location - IE should it be the carb side of the existing mechanical pump, or the tank side? Or...how about in-tandem as it were, using a "Y" connector at both ends of the pump inlet/outlets, this way surely the mechanical pump would not be affected at all by the leccy one?? TY again...Tim.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required