We have been smelling fumes intermittently on our 35 lightning. We don't smell it until we've been cruising and we reach our destination. One day it was strong, one day we didn't smell it, or if we did, it was faint. The assumption is perhaps fuel tanks have pinholes and have to replaced, but can't find any information on where they are located. Anyone know where they are, or hear of this problem before?

Under the cockpit floor.

great, and how does one get to the tanks in that case. second, know where the sending unit is? it could be that...

The sending units are under back seat. I had to replace the gas tanks on mine the bottom of the port tank had pinholes from corrosion. we smelled fumes in the cabin for a year the. One day when it was full gas leaked into the bilge where the fuel line comes thru bulkhead. It would stop when fuel was low. We a blow gun in the vent and pressurized the tank and you could see gas bubble up out of the foam surrounding the tank.

How big of a job is replacing the fuel tanks?

The floor has to be cut out, removed, tanks replaced then the floor glassed back in.

Gonna have to cut the deck, remove the tank, install and secure the new tank, and repair the deck ... not a small job for sure!

Are you sure it isn't just the fumes from the vents on the sides? I have noticed that when the tanks were really full on my last boat.

They don't cut the deck. It's all cut behind the seat and side panels. Only visible cut in in front of the cabin doors on the floor

Fountain did mine in 2006 for $10000.00