FUEL FILLER "O" ring seals. replacement ?

[Steve Kraus]

SEEKING assistance as follows;  

         1.  A source and /or precise O.D and I.D. and thickness for the "O"ring that "seats" into the groove under the deck mounted fuel filler cap. This seal is NOT on or in  the cap, but  is in a groove in  the base of the filler neck,  observable when the cap is removed. . The caps twist down onto the rubber seal. The APPROXIMATE dimensions:O.D. 2 11/16- 2 3/4" with a thickness of 3/32" or maybe 1/8" and is  imbedded in the groove about 60%. The reason the precise dimensions are important is the seal is a simple, dry, press-fit into the groove. As the cap comes down onto seal it can distort same if it has any free play)

              ( this seal must be perfect for water-tight fuel tank integrity. As the seal ages and is exposed to repeated compression-distortion, it loses the seal action; regardless how tight it is turned. Also, when it is 30-40 years old it is "time" !! )

         2. This is for the 26' sport cruiser 1986 model with 2 fillers; but I am hopeful any  gas model  could be interchangeable and assist .

Thanks in advance, Steve 

[Stephen Schwartz]

Have you tried askign Jeff harman? He is usually avail via the FB

[Brian Edmondson]

Hi Steve,

I was frustrated by this on my Tolly 26; and we may need a more experienced boater to wade in here, but I just replaced the o-rings on my 26 and they were substantially larger than the groove in the fuel deck fitting.  As my Tolly is 36 years old, I would doubt the o-rings were original, but it is possible.  After looking at it carefully, I decided that I liked the size of the o-rings.  I have misplaced my receipt and the name and address of the company near (or in) Ballard that has every o-ring you can think of.  I got their name and address from Fisheries Supply.  I was surprised that a comprehensive marine products provider like Fisheries had no o-rings even close to what I needed.  I couldn't find them at West Marine either.  

The larger o-rings sit nicely on top of the deck fitting and the cap can apply a lot of compression to the o-rings.  I'm not sure I would be comfortable with a smaller o-ring.  FWIW, here are the measurements I took with my digital caliper:  2.90" O.D.  x  2.45" I.D.  x  0.20" thick.  (or approximately 2-7/8"  x  2-7/16"  x  13/64").  I'm hoping we run into somebody who really knows this topic.  I have worked in pneumatics and rebuilt a lot of equipment that uses o-rings, including hydraulics, but there might be some marine knowledge that is needed here.  If I ever find the receipt for the o-rings I will post it here.

BrianE.

[Brian Edmondson]

O-RINGS:

Gardico Inc.

4912 14the Ave NW

Seattle, WA  98107

PHONE:  206-283-5850

[Brian Edmondson]

 Thank you Steve.  I think that's a good idea!  I am comfortable that the o-rings I am using will produce a good seal.  But I have NO idea if they match the OEM equipment.  My o-rings are too large to be captive in the groove.  But I have NO idea if these match the OEM equipment.  My o-rings are too large to be captive within the groove.  It would be my guess that the original o-rings sat down (captive) inside the groove in the deck fitting.  But, even though it might sound ridiculous, a fair amount of engineering goes into o-ring design, as we learned so painfully with the Challenger disaster (see side note below).  If you send me those o-rings I will spend some on it, but I don't have all the appropriate measuring tools so I will have to improvise.  One other thing I haven't seen yet are the OEM o-rings.  When I stopped in the stores, neither West Marine or Fisheries Supply had those deck fittings.  I'm going to talk to Fisheries about getting one of those in so I can look at the o-rings.  I often believe that I might be "over-thinking" stuff, but this is NOT a place where you want a failure point.  At least I don't.

I will send you my address in a separate email Steve.

BE

Side Note:  Speaking of o-rings... while waiting to testify in a product liability case in Kansas City in 1990 I was alone in a room with the whistleblower from Morton Thiokol for over two of the most fascinating hours of my life.  The whistleblower, Roger Boisjoly (who passed away in 2012) was one of two engineers that managed to sound the alarm on the high risk potential of an o-ring failure and for a few hours thought they had prevented the launch of the Challenger space shuttle.  If you recall, the launch was halted... but then that decision was subsequently reversed in a follow-on meeting that cut out Roger and the other engineer who had both fought passionately and worked very hard to hold off on the launch; as they knew the extreme low temperatures that turned Challenger into an icicle on the launch pad put the shuttle far outside of launch parameters.  Thirty years later this story is still not understood by a majority of Americans who don't know the answer to "why did they change their decision and force the launch?"  Roger told me, that after the disaster and the press coverage, Morton Thiokol moved him into an empty warehouse where there was only a desk and a chair.  No phone.  No nothing.  He was given keys to the building and told to be there from 8:00 am to 5:00 pm.  At first he told himself that he wasn't going to let them win, so he showed up every day, read books and collected a paycheck.  After about a month (if memory serves) he asked himself, "What I am doing, with my credentials I could go anywhere?"  So, he quit... only to  then find out that he was black-balled.  In time, he started his own consulting firm working with older, seasoned engineers who found themselves the victims of bean-counters, let go at the peak of their careers and unable to find work.  Roger had developed a program to show them how to start up their own engineering consulting businesses.  He also became a highly respected engineering expert witness, which is how I met him as we testified in a case where a carpenter swinging around a column with a Bostich pneumatic nailer... nailed another worker's hard hat to his head with a 3" nail.  I still have Roger's business card.  I wish we had the time to talk about hard hat design, but we didn't.  You ca't think of everything.

[Brian Edmondson]

Steve, I got the o-rings yesterday and will look at this ASAP.  We are dealing with a winter storm right now.  The o-rings you sent are DRAMATICALLY different from what was on my boat. They are much smaller in cross-section (skinnier)  As soon as I can get to my deck fittings, I will take some measurements.  At this point I really want to see the o-rings that come with a replacement deck fitting.  I'll keep you posted.

[Brian Edmondson]

Steve, I finally got a break in the rain and removed the fuel filler caps on my deck to check the fit of the o-rings that you sent me.  I was pretty sure they were too "skinny," but they are way too small for my deck fittings.  It's not even close.  

The o-rings I am using are too "fat," but - at least for now - they are making a good seal.  If the skinnier o-rings fit your boat's deck fittings, then we have very different fuel deck fittings.  I'm attaching pics.

I'm going to nail this down ASAP.