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Float bowl over flow

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jtb55

jtb55

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I have a 100 M vintage race car with SU H6's. Having seen two failures in the banjo connector between the float bowls on two other race cars I made up a aeroquip an6 replacement I had seen other racers use. However after installing it the aft float bowl overflowed ( no problem with the front float bowl) so I took it apart and replaced gaskets on the float bowl and cap nut. It still overfowed. Because the ID of the old connector was smaller than the ID new aeroquip line I thought that this maybe the problem and reinstaled the original banjo connector and it still overflowed. So I took the forward float bowl apart to compare the two, they looked the same. I went to my spares (Joe Curto) and noticed that my spare float needles were metal whereas my existing were plastic. I tried to remove the old seat (brass) but was unable to get a wrench on the old seat ( threads into the bowl cover) Any ideas as to how to get them out ? Also do the bango bolts that attach the old connector to the float bolts need to be alligned with the connector ? I don't think it is necessary because connector seems to provide a machined path to allow adequate fuel flow. thanks jtb
 
Hi JT,
The overflow is caused by a float needle failing to seal or an improperly set float level.

The best float needles in my opinion are Viton (rubber) tipped stainless steel with spring plungers in the bottom (float side). I have never had one fail to seal or to stick. They are commonly available. You can get the needle seats out with a properly sized nut driver. I forget the size. "Maybe 1/4". If necessary you can grind down the OD of the driver a bit for clearance. Use some penetrating oil & patience if necessary.

The float levels are properly set when a 7/16" drill bit shank will just fit between the top & the float with the needle plunger spring NOT compressed. Bend the needle contact tab on the float to fit.

You are correct about the banjo orientation.
Regards,
Dave

12/20/04 - I just checked, a 11/32 hex nut driver fits my needle seats.
 
HI JTB, Dave has just about covered the slice. If the defective needle was plastic and your spares are metal why not just replace the plastic needle with the steel one and leave the seat in place. However, in my opinion the best fuel control vave"Float Needles" for the SU carburetors is the Grose Jet. I know that Joe Cutro recommends and stocks them too.-FWIW---Keoke
 
Thanks all. My spares are from Curto, rubber tiped but do not fit the existing seats. thanks jtb
 
[ QUOTE ]
Thanks all. My spares are from Curto, rubber tiped but do not fit the existing seats. thanks jtb

[/ QUOTE ]

Then JTB,I think you have the wrong spares. Ask Joe about the grose jets mentioned above and the problem will go away.---Keoke
 
Did you check to see if your float has fuel in it? One of mine had a small leak and it caused overflow.

Walter
 
YEP Walter, you are correct, a defective float will certainly cause that problem.---Keoke /ubbthreads/images/graemlins/thumbsup.gif
 
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