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Yachtwork, Marine Engineer
Category: Boat
Satisfied Customers: 3202
Experience:  MEC3 and RYA Yachtmaster Ocean
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My fuel filler cap is seized on. How can I unscrew it best.

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My fuel filler cap is seized on. How can I unscrew it best. Tried mole type grips, also boiling water! Help!
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: Fuel filler cap on my westerly griffon is seized on and immovable. Tried mole type grips, or boiling water. No go. Help!
JA: Is there anything else the Boat Mechanic should know before I connect you? Rest assured that they'll be able to help you.
Customer: the tank is maybe half full.

I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.

I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.

Thank you!

Hello, welcome. Who do I have the pleasure of speaking to? My name is***** am here to help. I have been in the marine industry for 25+ years and have been a licensed Marine Engineer since 2009. I like to think outside the box and was part of the team that set the UIM Round The World Speedboat Record. I would like to be your requested tech when you have boat issues. I will be happy to help you.

I know that can be frustrating. Hopefully, we can get you back on the water quickly.

Are you at the boat now?

So the filler cap is seized onto the deck fitting. That can be tricky. One way some guys get them off is to put a cold chisel onto the cap and make a ding that they can then use to start tapping the cold chisel into the cap pushing the cap off. That is tapping the chisel so from above the cap is turning counterclockwise.

How does that sound?

Customer: replied 16 days ago.
I tried that as well, but no luck. My name is***** on the boat just now, but home in Gloucester. Boat is in Plymouth
Dang. Ok, next is to drill two holes in the cap. It drills easily because it's most likely brass. Then put a bolt in each hole, say 10mm, put a bar between the bolts and then force the cap off. Of course you will have to buy another cap after this, but the cap will be off.

How does that sound?

Customer: replied 16 days ago.
Ok, that sounds good, albeit drastic! I have to be away from the boat for a week or so, but I’ll try that next, thanks. I think it’s not brass but some sort of aluminium alloy, but I guess same idea will work. Having got that far, even if that won’t go, I’ll just continue to destroy the cap, drilling and sawing, after which of course a new cap. Unless you can suggest anything else? Maybe a plastic one that could be sacrificial if the same thing happened again, but is cheaper than the ‘proper’ one? (£40 or so!) Thanks for all your help, Scott!

You bet. The material that will last in the new fitting depends on the hull material.

Chromed Brass is great for steel, GPR, and wood but an aluminum boat is different. Are you an Al hull or just the fitting?

Customer: replied 16 days ago.
Just the fitting. It’s a grip hull

Great. Then we are doing right. Be safe out there.

I did my best to answer with the information I had. I hope it helped with the project.

You might want to mark me as a favorite Expert and then on your next question you can request me and we can pick up where we left off.

I hope I was able to answer your question. If you would like to ask me another question in the future, you can add me as a favorite Expert. You'll have the option to do that on your "My Questions" page if you choose to rate our interaction or you can request me by name if you wish. My name is ***** ***** I go by Yachtwork, Marine Engineer on the site.


Yachtwork, Marine Engineer
Category: Boat
Satisfied Customers: 3202
Experience: MEC3 and RYA Yachtmaster Ocean
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