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MG MGB Technical - HIF-4 Float setting

What is a good way to check the float hight on a HIF-4? Rather a novice at this, so don't make it to hard for me to understand. Thanks------------
Dale
PS Had the front carb float stick and could not see any problem when it was apart.
Dale & Barb Mast

I went around the garage with my micrometer measuring various bits of wire until I found one that was the required one millimeter diameter. I think it was actually a big paper clip, but not sure. If you don't have a micrometer, you can use a ruler and a good eye. (Borrow someone else's if need be.) Since the tolerance is plus or minus half a millimeter, it isn't critical that your measuring tool be spot on.

For a straight edge, I used the edge of a feeler guage.

Install the needle valve and float. Turn the carb upside down. I used a (clean, empty) medium-sized soup can to set the carb in. I think it was Progresso chicken with rice, but you may find another flavor works best if your car is green.

Use the straight edge to bridge across the base of the carb housing, through the "saddle" of the float. Then put the paper clip or whatever between the edge of the feeler guage and the lowest part of the float to measure the level. As noted before, the tolerance is half a millimeter, so don't make yourself crazy getting it perfect. Gently bend the brass tap which rides on the valve needle to change the float setting.

That brass tab will only have so many bends in it before it breaks. Don't use them up.

I'm told there are floats that don't have a brass tab - the part that pushes on the needle rather is molded into the plastic. In that case you have to get washers to put under the valve seat to move it up or down. Don't use anything that will rust or corrode. Brass or some sort of fuel-resistant nylon is probably best.

That's a rough description. I'm sure someone will come along to add some clarity.
Matt Kulka

Matt:
That sounds like it might work OK. Thanks!
Dale
Dale & Barb Mast

Despite the precision quoted in the manuals, which Matt gives above, I really don't think it is that critical. I was caught out on the road with a serious carb leak due to a failed float. To get me home without being an explosion waiting to happen I cross-connected the overdrive switch and fuel pump wiring to allow me to switch the pump on and off manually. When the car started to splutter I turned it on for a few seconds until I judged that the float chambers were full, then switched it off until it started to splutter again. This did not happen for a minute or two and during that time, with normal driving, there was no detectable change in how the engine was running, even though the float chambers were running between full or overfull and empty. FWIW.
Paul Hunt

This thread was discussed between 13/07/2004 and 14/07/2004

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