48 IDA fuel level

[priobe]

The reason why the F11 tube works well in many set ups is because the idle circuit is on the rich side, or it is just exactly the proper mixture for that setup.

One test you can do if you feel that the your fuel level is too high (depending on the etube) and you are running an electric pump is shut down the pump. If you are experiencing the problem say between 2000 - 3000.

This will lower the fuel level, uncovering the holes on say a F16, this will let you know you will need to lean out your emulsion tube or lower you fuel level.

Also, try to stick to the same diameter tube and concentrate on the hole level. By changing to a different tube say F7 to a F11 or F16 is like making multiple changes because each of these tubes are different diameter with holes placed at different heights. There is not common ground with any of the mentioned tubes, so how do you know what you have changed compared to what you came from.

This is why I posted a thread last week about emulsion tubes, which I guess was not interesting (sorry).

I have been experiementing with this for awhile now and with a 245 /250 and 680 lift camshaft, I am able to lower my idle jet to 70 (holder) and 60 fuel.

On the LM1 my reading are 18 A/R at idle and on the gas/underload I go to 2000 rpm it goes to 13.5. ( no popping)

On 2000 to 3000 I get 12.2 then goes to 11.8 above 3000.

I am experiencing no pops at all except on decelleration and then it is only 2 or 3 pops then it is fine.

Find an open road and play with your circuits.

Also,I am running a 55 exhaust valve. I also noticed that if you think you are holding the gas pedal steady to not engage the pump circuit, then you might be mistaken.
The slights movemement will engage that circuit throwing you off.

Many people say to use a blocked bypass but I prefer to tune the carbs without the aid of a pump jet. and only use the pump jet to fill in only if needed.