Fuel filler

[billyfish]

I need to replace my filler cap but when it came to ordering one they are 1.5" or 2" ID . Stupidly I measured OD which was 2" does that mean the ID will be 1.5" or are there variables?

 

[Boater Sam]

I need to replace my filler cap but when it came to ordering one they are 1.5" or 2" ID . Stupidly I measured OD which was 2" does that mean the ID will be 1.5" or are there variables?

If its a malleable iron BSP thread cap it is quite possibly 1.5" BSP The ID of the pipe is the size criterion.

 

[VicS]

I need to replace my filler cap but when it came to ordering one they are 1.5" or 2" ID . Stupidly I measured OD which was 2" does that mean the ID will be 1.5" or are there variables?

You don't say what you measured
Deck fillers are usually sized according to the bore of the hose they fit . 1.5 " bore fuel hose is about 2" OD

 

[Tranona]

Don't think there is standard sizing or threads on filler caps. You may be able to identify the make which will help. Do you have another filler of the same type on the boat to try and if it fits use it as a sample.

 

[billyfish]

Thanks. I'm sure its 1.5"