R25 faulty fuel guage

[MikeAndLorena]

The fuel gauge on our newly purchased 2007 R25 registers "full" all the time that the ignition is on. Anybody know how to access the fuel tank and sensor/float?

 

[Levitation]

Turn around from the helm and face the rear step. In the floor of the walkway, near the door to the head, is a round hatch plate in the floor. Under that.

 

[elly]

I have a 2008 R25 and it did not have an inspection port on the floor. I ended up cutting a hole . This gave me access to the fuel fill, vent and return lines. The fuel sender is located forward of that by a couple of feet. Check the tech. bulletin section for a line drawing of the fuel tank. If your boat is similar to mine you will need to cut a hole. Newer boats came from the factory with the access ports installed.

 

[MikeAndLorena]

Thanks. I was afraid of that. My 2007 has no inspection hatch there. How big of hatch did you end up cutting?

 

[Spudnuts]

We have the same problem on our newly purchased 2008 R25. Andrew told us to check the SmartCraft trip log for fuel used (“environment” setting - sunshine icon) and subtract that from the 75-gallon full tank to determine how much is left. According to Andrew, the reading for fuel used is always much more accurate than that for fuel remaining even when the sensor is working. He also told us that the sensor can start working again (which it did) when the fuel level goes down a bit and you’re out in choppy seas to jar it loose. At any rate, the math works fine for us, so we don’t plan to cut the floor to access the sensor.

 

[Spudnuts]

Be sure to reset the trip log when you fill the fuel tank.

 

[elly]

I cut a hole for a 6" round inspection port over the fuel fill, vent and return lines. I did this to access the fuel vent hose. My fuel vent was located on the starboard side of the boat and when I added fuel it came gushing out of the filler neck, even when adding 10 gal. I ran a new vent line to a new vent (another hole) located next to fuel fill. I also added in a whistle device that signals a full tank.

My boat w/ yanmar 110 does not have any fuel monitoring .

Now that it is added I can say that cutting holes was not a big deal.

 

[captstu]

My 2011 R-25 with a Yanmar 4BY2-150 has developed a minor fuel puzzle.

As I travel, the digital "fuel in tank" reading on the Garman always agreed closely with my pencil and paper calculations of the fuel using the burn rate * hours run. When it came time to refill, the fuel added agreed closely with the total - "fuel in tank" reading. Both these readings agreed closely with the fuel guage present on several of the information/engine screens. All was golden.

When I topped off the tank and pressed the "add fuel to tank" button, the "fuel in tank" digits agreed with my setting of maximum fuel and the analog gauge "snapped" from the level before the fill-up to full. This led me to believe the analog gauge was just a synthetic fuel gauge run off the "fuel in tank" calculation.

This was confirmed by another discussion on this board that said the generator consumption was not measured by the "fuel in tank" number - and was not reflected by the analog gauge.

This was confirmed by experience when I ran the generator and air conditioning all night and consumed no fuel. Since I knew the approximate bun rate of the generator, I simply subtracted that fuel from the digital amount shown on the garmin and all was still golden.

Yesterday, the pointer on my analog fuel gauge disappeared for an hour or so. I looked on the floor and it wasn't there - but no problem, an hour or so later, the pointer came back in approximately the right place.

Is there a mechanical sender I should replace? If so, how do I access it? The inspection opening just to the starboard side of center about 2' inside the door has nothing resembling a fuel level sensor that I can see.

No big deal, the digital instrument is preferable, I'm just curious.