Gas cap won't open

[Marine36]

I went for a ride today. A very pleasant day it was.

Now I have a problem. I stopped and got fuel. Returned home to add some Sea Foam and found that the gas cap will not open. Let me clarify the key will only partially go in.

I can get a new cap. But how do I get the old one off?????

Please impart your wisdom and knowledge upon me.

[Guest]

Tap on the cap first.
Spray some PB Blaster in there.

[skidMarkNZ]

Mine did this once at a gas station.... gas station in rural nowhere.... me out of fuel.... had to use a screwdriver to pry the old one off.... then filed off the lugs to make it a spin on cap...

[Marine36]

Gas cap opens. Never could wriggle the key in so I knocked a screwdrive in the slot and now it opens with a key or with a screwdriver