Remote impulse fuel pumps very rarely give you any trouble.There was 4 in the parts box when I bought the business 6 years ago & I have only used one of them.
There is a small sintered brass filter that can get clogged which limits the pumping action as air can not escape fast enough.
Did you remove the pump ?
If so the intake is on the side nearest to the impulse line and the output is on the other side.
There is a check valve on the output on cheap ones and a check valve on both fuel lines on the expensive ones.
A mower will run for near 2 minutes on a float bowls worth of fuel which is 1 to 2 ounces so the pump does not have to shift a lot of fuel.
Remove the impulse line and hold some tissue near the end.
Start the engine and you should see the paper flutter.
I used to use the old tounge till some one here suggested the tissue, not as tasty but stops the nose getting burned.
When you reply to Gonzo with the make & model numbers, also post the symptoms you are having.
The internet is free ( well sort of ) so don't be shy.
There is no such thing as too much information.
