Thought we'd put this out there for those who have fiberglass tanks or are considering a boat with them, Like alot of marine repair shops and vintage boat owners for the past several years we (like others) have been seeing leaking and seeping and deteriorating fiberglass fuel cells in some of the mid 70's boat equipt with Fiberglass tanks As most know these tanks are profoundly affected by modern fuels and can deteriorate from the inside out over time , Over and above the obvious danger of fractures , leaks to bilge fumes etc we've also seen slimy brown discolaration and residue in fuel , fuel feed and fuel filter issues and general runability/carb issues. But this is the result of one of the worst the so far . These pics are from a 429 BBF from 74 Cambell V-drive we have in process , It initially came in for fuel tank replacement/upgrade with an "oh by the way it also hasn't been running well complaint too!" Have replaced the Glass tanks and all fuel related plumbing and decided to run compression and cylinder leak down , finding two cylinders with "0" compression and bent push rods it was time for tear down , heres what we found today, this engine will have to come completley down ...
black syrupy residue in the cylinders
Sticky residue in the intake ports
Black goo in an example cylinder
intake valves stuck open from molasses like residue on stems
typical valve, stem residue