Another Carb Fuel Leak. Please HELP!!!!

[flyanimator]

That was on my mind and I did take that into consideration when bench testing. I actually had the fuel res. about 8 to 10 inches above the carbs.

[Matchless]

Could you prove which carb was leaking?

[flyanimator]

it was carbs 3 and 4 that were leaking

[Matchless]

it was carbs 3 and 4 that were leaking

Have a carefull look at each one in turn:

1) Check that float height is correct.

2) Pull the needle and seat

3) Inspect o-ring

4) Inspect the tapered tip of the needle for any ridge or marks on the tapered face, this the part that seals against the seat and closes off the fuel flow(use a magnifying glass)

5) Inspect the inside of the seat tapered face for marks, dirt or scoring, use a light and magifying glass). This is not easy.

6)If they are bad or suspect replace them as a set only.

7) Inspect the large opening for roundness just inside the neck, if someone ever pulled these out with pliers thay may be ovalled. A new 5.2 or 5.3 mm drill bit will hlep you determine this.

8) holding the seat with the large opening facing down you can gently push the needle up into the neck and as you move your finger down ensure that it does not stick even sightly on the edge. Do this by turning the needle a small bit every time as one of the corners may be catching at times.

9) If they are ovalled replace again only as a set.

10) If unobtainable or an urgent repair is required, wrap a 1/2" strip of 1200 sandpaper around a hex key and gently polish the inside of the large opening. Do not go any deeper than 1/4". Do not touch the brass sealing face at the other end!

11) Once you are sure nothing seems to be out of order blow in from the small end while gently holding the needle pushed against the sealling side (tapered) It should block off.

12) put it back in the carb, set the bank of carbs level and put some fuel in a temporary container, connect to carb and see if it stil leaks.

13) If it still leaks it is likely that a PO may have installed non matching needle and seats from different manufaturers. Thery may have swopped needles from other carbs or you may have missed something.

14) Always keep the needle and the seat from the same carb together as either may have more wear than another and not seal properly if mixed. Always replace these as a set as different batches, manufacturers may have different specs and the faces may not be exactly complimentary and be the cause of your headaches.

15) Do not be misled in that carbs overflowing is due to a bad petcock or having it on prime! The vacuum function on the pertcock is for additional security, shutting off any fuel flow when not running even if you needle and seats leaks a bit.

Hope this helps a bit.