Lapping float seats?

[wyo307]

Can someone please explain to me the best method for lapping in my float seat? What is the best compound to use? Best practices etc. I have a carb for my zephyr that continues to allow fuel to flow past the seat causing the motor to flood and fowl plugs when idled down. I have resealed the cork a few times but that didn’t help so now I’m suspecting a burr in the seat causing the problem. On a side note does anyone know of a substitute float that I can use in a zephyr? Thank you for your help.

[George Emmanuel]

Most of the seats I’ve seen have a sharp edge rather than a taper because the needle has the taper. Try this,–with the float removed and the needle in the seat, make sure the needle is straight in the seat and give it a light tap with a very small hammer. I’ve done that several times with continued success. I assume in saying this the needle is stainless and the seat brass?

George

[frankr]

X2 what George said. In the hydraulics plant where I worked, that was called "coining" the seat. I must have done about 10 bazillion of them. But of course it won’t work if there is serious damage to the seat.

[Anonymous]

Did you float the float in a cup of gas to make sure it’s buoyant?

Steve A W

[jeff-register]

I have used valve lapping compound & finishing compound to reseat metal needle & seat set ups. Coining before lapping is standard as well.

[wyo307]

Thank you everyone for the suggestions! I will start by pulling it back apart and floating the float along with attempting to "coin" the seat. If that doesn’t work I will get some super fine lapping compound and try that. FYI both the needle and the seat are brass and the needle came out of a different carb for a later model zephyr.

[chris-p]

As stated, ensure that the float is not your problem. I have seen where owners put too much coating on , and then would not be as buoyant, due to the extra weight.

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