Fuel fumes in cockpit

[N427EF]

Although, possibly coincidental, I seem to notice it most often when boost pump is on

It is very possible that it is simply a little spilling from the vent lines, like many others have noticed on their planes. The fact that you stated it was most often noticed when the boost pump is on, tells me there is a tiny fuel leak somewhere. Inspect thoroughly upstream of the boost pump. It takes very little fuel, even just a little weep that will be noticeable by your sense of smell. In any case, when you inspect the fuel lines with a flashlight and a mirror you'll notice blue stains around fittings, if there is a leak.
I flew my 8 for 450 hours and only noticed a little smell on rare occasions when the tanks were full.
On the other hand, I had a smell of fuel in my 10 when the boost pump was on for landing and found a tiny weeping leak around the nipple on the fuel flow sensor.
It's tight now and there is no more smell whatsoever.

[Wayne Gillispie]

I had a leak downstream of running boost pump that dripped every 5 minutes. No stains but faint smell during avionics setup. I found it with this...

http://www.amazon.com/UEi-Instrument.../dp/B000HHTY7Q

You might also try borrowing one from your HVAC guy or offer a ride after he locates your leak and you repair it.

[g zero]

Try putting a rubber grommet where the fuel vent passes thru the landing gear inspection cover , might even consider a gasket between the cover and bottom of the fuselage . There is nothing sealing the line as it passes thru the gear tower , and floor .
Tom

[DanH]

Originally Posted by Ironflight

The -8 is well known for getting some fuel fumes sucked into the NACA scoop under the right wing and then into the cabin through the passenger vent. I find it happens with full tanks, particularly when the right tank is really full and I am descending in the pattern. If I burn ten minutes of fuel out of the right, I don't get the smell.YMMV

Mine exactly the same.