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Discussion Starter #1
http://www.rexmar.com/page15.html

I have these on my boat right now. They do have a tiny rubber gromet around the cap but it doesn't seem to be enough. Even with 10 gallons in a 15 gallon tank and its still leaking right out & around the cap.
Just wandering if anybody else has this problem. Think I might switch to a different cap.
 

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BTC cardcarrying member
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I'm running the vented ones with no problems. i have 2 22gal tanks and put 20 gal in them, If I let it sit in the sun full on the trailer they will leak other then that it's all good.
 

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Discussion Starter #5
Uh so whats up with mine? Maybe just have to replace the rubber gromet.:)coffee
Thanks.:)
 

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no need 2 fake it.
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i wish i could use flush mount caps... mine are mounted right on the contour of my boat so they cant be round- have to be oval, sucks
 

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E-7 Sheepdog (ret)
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My flush cap sits vertically on the back, is 30 years old (original), is not vented, is o-ring sealed, and has never leaked, in or out.

I DID replace the o-ring 2 or 3 years ago.
 

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Our caps come std configuration vented. In other words there is a passage bypassing the o-ring to let air in or out as demanded by fuel use or temperature increase or decrease. It is possible you are passing fuel out these vent holes. Not knowing your configuration it's hard to say. This not an uncommon scenario if tanks are almost full and boat is left in the sun. Also if too full splash can run out the vent holes. Especially a problem with small boats that have short fuel fill hoses going to the tank(s).

If the orings themselves are bad (a rarity) we have replacements. But unless they have cuts or something in them I doubt that's the problem. In any event make sure you use Viton (flourocarbon) orings if you get them somewhere other than from us. Standard Buna orings will swell up with fuel and become useless in a short time. Most standard orings you'd find at auto parts or hardware outlets (Buna or Viton) are also too soft a durameter (measurement of hardness).

Caps are also available non-vented (we seal the threaded hole with a small set screw). But if you run non-vented caps you have to have an external vent elsewhere to the tank(s). You must have a vent somewhere.

Hope that helps.
 

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Discussion Starter #10
Our caps come std configuration vented. In other words there is a passage bypassing the o-ring to let air in or out as demanded by fuel use or temperature increase or decrease. It is possible you are passing fuel out these vent holes. Not knowing your configuration it's hard to say. This not an uncommon scenario if tanks are almost full and boat is left in the sun. Also if too full splash can run out the vent holes. Especially a problem with small boats that have short fuel fill hoses going to the tank(s).

If the orings themselves are bad (a rarity) we have replacements. But unless they have cuts or something in them I doubt that's the problem. In any event make sure you use Viton (flourocarbon) orings if you get them somewhere other than from us. Standard Buna orings will swell up with fuel and become useless in a short time. Most standard orings you'd find at auto parts or hardware outlets (Buna or Viton) are also too soft a durameter (measurement of hardness).

Caps are also available non-vented (we seal the threaded hole with a small set screw). But if you run non-vented caps you have to have an external vent elsewhere to the tank(s). You must have a vent somewhere.

Hope that helps.
Thank you very much for your reply. I went out in the garage and checked it out. Your right...short fuel fill hose. My caps also are vented. I have gas spilling out of them while trailering out to the lake. So this problem has to be addressed. Any suggestions would be great!
Thanks,
Nate
 

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jetboataholic
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Thank you very much for your reply. I went out in the garage and checked it out. Your right...short fuel fill hose. My caps also are vented. I have gas spilling out of them while trailering out to the lake. So this problem has to be addressed. Any suggestions would be great!
Thanks,
Nate
You could seal off the vent hole in the caps and install the external vents to your tanks.:)bulb
 

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....like warm apple pie
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I've got the same cap, no problems....
I ran the same caps for 10 years. I only had an issue once.....and a buddy of mine cross threaded the cap after filling the tank (not sure whether the free tank of gas was worth it). The threads on mine were really fine. I ended up replacing the setup once I realized what had happened. Other than 'human error', no issues at all. Keep the O ring lubed with vasoline and youre good to go.

PS: Do not over tighten them....a bitch to take off!!
 

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What about making yourself a little "Splash" plate on the bottom of the cap that lets air escape but directs splashing fuel away from the vent hole? Maybe use the bottom of a small stainless cereal bowl or something, and cut it so it is just a bit smaller than the fill neck and bolt it to the base of the cap. Maybe that's too booty fab? Just an idea?? Fortunately it wouldn't be seen if it looks funky or doesn't work.

~Brian
 

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I have an idea for something that would work and have been thinking about it for quite awhile. It would bolt into the fill cap. I may make some and try it out. Unfortunately it won't be tomorrow or next week.

Anything like this will stop "splash". But won't stop "surge" of a tank that's too full driving solid stream of gasoline up the fill neck when stopping or starting.

The bottom line may be you have to tow with less gas in the tanks till you get close to destination.

Another fix for towing only I though about would be to use one of our set screws we use for the non-vented model and drilling a tiny hole in the middle and inserting in cap for towing. The tiny hole would allow air escape but not much fuel. You would have to make sure to take it out tho before running the boat. Not real failsafe in that regard but might be effective towing .
 

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Discussion Starter #15
Thank you guys for your ideas. Time to go out in the garage and ponder this over a few adult beverages...
Thanks Brian & REXONE!
 
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