Triumph Repair: Fuel Leaking from Anti run-on valve, charcoal canister, manifold vacuum

Question
Good Day,

I am the original owner of a 1980 TR7 convertible with 33,000 miles.  The car has always been garage stored.  Most recently the car has been stored in the garage for 3 years without running it.  I have put in a fresh battery, checked fluid levels and the engine started right up.  I backed it out of the garage and before I left the drive, it was leaking gas.  After leaving the car sit over night, I started it up again and it is running fine, but gas is pouring out of the bottom of the Anti run-on valve.  Any ideas?  I have also replace several engine hoses that were cracked and leaking. I would appreciate any assistance you can provide on how to correct the gas leaking problem.  

Thanks

Michael Surma

Answer
Hi Michael,

Gasoline from the anti-dieseling valve can come from several sources. The vent from the fuel tank goes to the charcoal canister as does and the air vent from the float chambers of the carburetors.

An over filled fuel tank can force fuel up to the canister and on to the anti-dieseling valve. Also a flooding carburetor can force raw fuel to the anti-dieseling valve.

Any fuel that gets into the charcoal canister destroys it and you must replace it to put the system back as designed.

The anti-dieseling valve applies manifold vacuum to the vent system of the float chambers when the key is turned off, thus preventing any fuel from exiting the main jet. This was BLM's method of stopping "run-on" or "dieseling" as it was called. Some local and federal laws are violated if you alter the system and that is why most shops will not alter the system for a customer.

Howard