R21 Fuel Tank Vent Line

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N

Newf

Well-known member
Joined
Apr 10, 2014
Messages
319
Fluid Motion Model
R-21 EC
Vessel Name
Saltwater Joy
I have a 2014 R21 and there is an issue when in choppy water or when I'm towing the boat. Fuel belches out of the vent that is located on the starboard side of the tank . Searching other post on this site I notice that this has been an issue for some time. It was also noted in one post that this was addressed by installing a longer hose extending from the port side of the tank to the vent inlet/outlet which has been relocated to the the starboard side. This has not addressed the problem as fuel still splashes out with as little as 1/4 of a tank remaining. Has this been addressed in the 2015 model? Should the line not have some type of one way check valve or at least a higher mounted vent inlet/outlet point? How can this current setup meet environmental standards???? Thanks in advance for your response..

NOTE: When trailering my boat I install a cap over the vent to prevent spilling while I'm towing but you should not have to do this. A redesign is required.
 
Newf":3e0mqsjn said:
I have a 2014 R21 and there is an issue when in choppy water or when I'm towing the boat. Fuel belches out of the vent that is located on the starboard side of the tank . Searching other post on this site I notice that this has been an issue for some time. It was also noted in one post that this was addressed by installing a longer hose extending from the port side of the tank to the vent inlet/outlet which has been relocated to the the starboard side. This has not addressed the problem as fuel still splashes out with as little as 1/4 of a tank remaining. Has this been addressed in the 2015 model? Should the line not have some type of one way check valve or at least a higher mounted vent inlet/outlet point? How can this current setup meet environmental standards???? Thanks in advance for your response..

NOTE: When trailering my boat I install a cap over the vent to prevent spilling while I'm towing but you should not have to do this. A redesign is required.
Click to expand...

Hello Newf,

I have a 2013 R21EC that DOES NOT have fuel 'belching' issues. You're right, there is a known problem with circa 2007-8 MY 21ECs. I thought the factory had come up with a 'fix' for that issue. On my boat the fuel is filled from aft/STB . The fuel tank vent originates from the aft/PORT corner of the fuel tank and has a long hose connected which runs to a deck fitting just lateral to the fuel fill point (on the STB side). So, the vent line is probably 4-5' long and slopes downward from deck fitting toward the tank. This set up works well.

The factory should be able to help you.

/dave
 
My 2014 R21EC spilled fuel from the vent when subject to boat wash at our marina. I was advised cut a few inches off the vent hose to make sure there was no sag in the line between the vent and the tank attachment. I had watched what happened in the tank when the boat was rocking and saw the wave strike each end of the tank and slap straight up the end to strike the tank top with enough force to push a small amount of fuel into the sagging vent hose. Removing this sag seems to have solved the problem. I think a better solution would be to have vented the tank in the middle instead of at one end.
Hope this isn't too late to be of use to someone.
Stu.
 
Hello Stu,

WELCOME to Tugnuts! You are never too late with a solution.

I'm glad the fuel sloshing problem has been solved. When others search the forum, your post will remain.

dave
 
We just noticed fuel spill from our 2014 R21 and tracked it to the fuel vent. Apparently it was the result of a belch similar to what is described here. Our tank is about half full. It does not appear that there is a sag in the fuel vent line nor that there is any excess vent line to cut off. Has the Ranger factory developed an opinion or recommendation?
Mike
 
Same problem (2016 model). The factory solution is to shorten the vent hose so there is no sag to trap fuel (I cut off 2-1/2"). However, the hose cannot be pulled tight enough to prevent zero sag in its length. I supported mine in three intermediate places along the top of the fuel tank for a gradual slope. Problem solved.

CN
 
When you pull the line tight, wear gloves or else you will slice your hands up on the fibreglass edges. There's not much room to work in there. Supporting the line with spacers so you have a gradual incline all the way to the vent (as others have done) is a great addition.

An integrated moulded rail along the inside back of the boat so that the vent line can simply lay in it, or some clips that could be adjusted etc. would be very helpful and would probably alleviate this ongoing issue.
 
The backs of my hands have just about healed... 🙂

CN
 
Our R-21EC was delivered to us Aug 26 this year. So it's one that was obviously very recently built. Andrew and I checked the fuel vent hose installation in the factory and it was ensured to be tight and without any dips between the vent and the tank.

With the fuel tank full the boat has been trailered about some and I've seen no evidence of diesel fuel venting on the transom. I hope this also means no fuel burping when in rough waters or simply rocking/rolling.

I took a few photos of the fuel tank vent hose to show how the factory installed mine. I also post a photo of the embossed fuel tank specifications. N.B. the tank is a 19 gallon / 7.2 liter capacity, 😱 (7.2 L does equal 19 US gallons).

Note the small white block that presumably holds the vent hose above the tank's surface and stops it from ever sagging. There's just this one support block and the vent line runs in a straight line from the support block to the vent outlet over on the starboard side.
IMG_0591.jpg


IMG_0594.jpg


19 gallons / 7.2 L fuel tank
IMG_0595.jpg
 
Must have been an option that I didn't select... :roll:

CN
 
Hello Barry,

YIKES! Get out your app cuz 7.2 Litres CANNOT equal 19 US Gallons. Recall that a Litre is JUST OVER one quart. Look closer at your pic of the tank label...it's 72 litres - not 7.2.

Or where you joking? :lol:

CN: You didn't miss out on an option.

dave
 
YIKES indeed! 😱 Those annoying decimal points. :lol:
 
Captain Nice":39mu17ag said:
Must have been an option that I didn't select... :roll:

CN
Click to expand...

Hahaha... I know the feeling! :lol:
 
Hi all: I have written about this before. My fuel tank still 'belches' when in choppy water. My Tug is a 2008/2009 model. The chrome vent on the port aft gunwale, next to the ensign staff, was never connected to the tank - merely blanked off (it looks good, but now all it does is providfe an extra vent for the aft compartment).

The fuel filling access point is on the stbd gunwale, as you would all know. Half way down the fuel filler pipe, there is a T-connection, from which runs a black hose, acros the top of the tank and joining to a pipe on the port side of the tank, into which runs excess fuel resulting from port and stbd surge. As well, inside the fuel filling point stainless steel cap, there is an O-ring, plus two vent holes. These vent holes allow fuel (forced upward from surge action) to escape from under the cap and onto the gunwales, which then sloshes around and over the side in heavy weather.

I have renewed the O-ring inside the cap, however the vent holes are designed to by-pass the O-ring, thereby allowing the tank to breathe. I still have not corrected the fuel belch problem and would apreciate anyone's suggestions. Regards, Stevan.
 
If you want to make the vent arrangement like the newer ones, which seems to solve the problem assuming proper slope of the vent line, you could (1) install a chrome vent on the starboard side and connect the existing vent hose to it, (2) cap the tee in the filler pipe and (3) replace the vented cap with a non-vented one. A bit of work in a tight space but doable.

CN
 
I wonder if a brass in line valve, installed on the breather (vent) line, might do the trick. You could almost close the valve so that only a very small amount of fuel would slosh through the valve, but not enough to get up to the deck fitting. The valve would have to be open enough so that some air would still enter the tank as the engine sucks up fuel. What small amount of fuel that sloshed through the partly closed valve, would get sucked back into the tank as the engine runs, I believe this system would also work when the boat is being trailered. It is important not to get a sag in the fuel line, as this causes a blockage of the fuel line which the engine may not be able to suck through. I think I might try this system on my 2014 21EC, but would appreciate any comments.
Andrew
 
I don't want to drill another hole through the hull, and since the vent is in deck, it might be better just to use an in line surge protector also made by Atwood
 
Most inline surge protectors seem to need mounting in an upright or at least on a 45 degree angle. There just isn't enough room above the tank in the R21-EC to do that. I think even the brass t inline valve has the potential to allow small amounts of fuel past it and once enough fuel gets on the other side of it (especially if you have even the slightest slack in the breather hose) you will get fuel out of the breather.

I think the item that CaptCrunch has mentioned could work. The other thing that could work is the vent tube running into a small fuel container, mounted on the floor just in front of the tank. On top of this small fuel container you have one of the inline surge protectors connected that then routes out to the boats breather vent. Any fuel sloshing out of the tank would be captured in the fuel container and could not get past the in line surge protector. This would allow the height necessary to mount the surge protector properly. The downside is that you would have to check the fuel container and keep it somewhat empty, however I imagine it would take some pretty rough weather and some time for the container to get full.

Personally, I believe that building a carefully constructed ramp that rises gently from the vent exit on the tank to the vent exit on the boat, will alleviate at least 99% of the fuel spilling. No part of the vent hose can be lower than where it exits the tank.
 
I guess that would be similar to the coolant expansion/recovery setup in cars (or in boats, too, for that matter). The tube from the fuel tank reaches almost to the bottom of the reservoir, where it would become submerged in the "sloshed" fuel. The vent tube ends near the top of the reservoir. Presumably and hopefully, any fuel that sloshes into the reservoir would get sucked back into the fuel tank (assuming the whole setup is air-tight). However, if space allows, I think I'd want it all to be above the fuel level of a full tank (maybe at a fairly remote location) to minimize the risk of leaks or siphons. Might be worth trying (or at least worth more thought).
 
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