Gas Cap Gasket

[earlbuddy]

I'm looking for the rubber gasket that goes under the gas cap on the 6 gallon metal tanks. It's not shown on the parts diagram.
Thank you.

 

[fitz73222]

Any boat shops or marinas near you? Assuming you are looking for the old style OMC non vented cap gasket, they are everywhere, laying in a pile at your favorite boat shop. I have 6 of those tanks up in the rafters...They're everywhere!

 

[Edchris177]

You can buy a replacement cap.

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1975&hp=9.9&model=10524C&manufacturer=Evinrude§ion=FUEL+TANK-6+GALLON

 

[fitz73222]

You can buy a replacement cap.

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1975&hp=9.9&model=10524C&manufacturer=Evinrude§ion=FUEL+TANK-6+GALLON

You can buy a replacement cap.

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1975&hp=9.9&model=10524C&manufacturer=Evinrude§ion=FUEL+TANK-6+GALLON

LOL, I picked a 1972 40 hp to look up the cap...

 

[Edchris177]

Yeah, they show it for every motor that has “fuel tank” in the parts lists, for decades.

 

[Droid]

I don't remember a rubber gasket on OEM tanks. I'm thinking it has a spring steel type flexible flange??? And yes, no seperate seal is shown in parts book.
The aftermarket Tempo tanks I remember having a gasket.
But I certainly can be wrong.

 

[Edchris177]

I have a bunch of tanks, both the 5gal, (Canadian gallon, about 22 litres), & the smaller half height ones. I usually include a clean one with motors I sell. They can be had here for $5-$15 CDN, & make for an easier sale.
The earliest ones, (I think they’re painted with Cruise-a-Day), have a cork gasket. Later ones have a rubber gasket.
The cork, or rubber sits on the spring flange, which works sort of like a cam. You can feel it engage, & create a tight seal as you turn the cap the last 1/4 turn.
The corks is often worn beyond use if the tank was heavily used. The rubber ones seem mostly bulletproof.

 

[Droid]

So there was a gasket but never a serviceable part.

 

[Fun Times]

Johnson Evinrude OMC OEM Gas Tank Cap Gasket, 0763906

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https://www.marineengine.com/newparts/part_search.php?part_num=0763906+

NEW Genuine OEM Evinrude Johnson BRP OMC 0763906 Gasket - Gas Cap 763906 | eBay

NEW Genuine OEM Evinrude Johnson BRP OMC 0763906 Gasket - Gas Cap 763906 This is a genuine OEM Evinrude Johnson BRP OMC factory original replacement part, not aftermarket

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[Edchris177]

I’d have to see a real photo of it. It may well be that the included diagram is not representative of the actual part.
I don’t think an O-ring would be very good, it would twist off the mounting flange of the tank when turned, there is no groove to keep it captive in place.
The originals are flat, about 1/4” wide.

 

[Edchris177]

Regrets for the delay I decided to escape winter and hide out in the Caribbean for a few weeks.
There is no spring to create seal pressure.
both the earlier tanks with the cork gasket and the newer ones with either the manual vent screw built into the cap or those that vent through the little pins on the fuel line connecter work the same.
They employ a ramp, (cam), which is built into the flange that the cap goes on. You can see it in the photo where it starts all almost flush with the flange and then slowly slopes down downwards. As the cap is turned, the lugs on the cap, force the cap tighter against the top of the flange, making a seal between the flange and the rubber gasket.
A gasket could easily be made out of any rubbery material that is fuel proof.