Oscillating fuel meter ribcraft

[Leapy]

Our RC 5.3 came with a verbal warning from new not to totally rely on the fuel guage, rather to use it as an indication only. In reality, it's fairly accurate when the boat is level and at rest. Underway, it's pessimistic depending on trim and sea state. It fluctuates mildly underway but certainly not wildly...possibly of the order of +\- 10%. We log our journeys for distance from the GPS and brim fill the tank on occasion so we can accurately calculate average fuel consumption. With this mpg data the guage is accurate enough to aid passage planning.

[free]

Can anyone post a picture of the gauge / sender used by Ribcraft? I think they're WEMA units. I like to know what I'm talking about before I post rubbish.

free

[AVRibber]

I'm not at my boat at the moment, but the instument itself is a WEMA indicater , I don't know if what's in the tank also is from the same mark

[free]

I'm guessing something like these? Can any other RC owners confirm?





free

[Leapy]

Can't comment on the sender but the guage is nothing like ours. Think ours are Suzuki?

[Pikey Dave]

My last one was an LED type, didn't bother with a gauge on this one, due to being useless. I still had the senders in the tanks & had them connected into my I-command/nmea2000 network, still useles. Continuous "low Fuel" alarms everytime you hit a wave. I use the EMM (engine fuel flow) now as my fuel remaining source & it is bang on whatever the conditions.

[free]

Originally Posted by Pikey Dave

I still had the senders in the tanks & had them connected into my I-command/nmea2000 network, still useles. Continuous "low Fuel" alarms everytime you hit a wave.

This kind of supports my findings so far. The WEMA gauges are undamped and the sender unit pictured is also undamped, it seems to be the one regularly fitted, after a fairly extensive trawl of the net. Admittedly it's a lot better than a swing arm type, but it's not right. WEMA makes an SD damped unit, but I'd bet next months wages on not many of them being fitted. Essentially, the same sender as above sits in a sealed tube with a small hole(s) top and bottom. This results in the fluid around the sender having a lag of several seconds, effectively damping out the oscillations.

Back to the OP, I don't really think he was expecting to be told to buy a new engine when all he wanted was to fix his fuel gauge. There's clearly something wrong when over 50% (30/50) of the tank volume is not read by the gauge. I'd be looking at the physical positioning of the sender, the length of the sender and finally checking that the resistance range is 0-180 ohms (I'd personally check the resistances at the gauge end rather than the sender itself.) These are reed switch types, so will never give a true linear reading and it would only take a couple of faulty reeds to make them effectively useless.

Bouncing between empty and full may just be the result of ineffective damping, but I'd also be checking all earth connections and feeds for high resistance, dead shorts and intermittent breaks.

free

[Pikey Dave]

The advice to buy a new engine was given with a teensy weensy touch of humour, a bit like the part in the microwave manual that tells you not to use it for drying your pets.

ee lad, tha can't educate pork

[jambo]

Hi Free
I had to renew my sender some three years ago direct from RC and it is the same as your photo. It was a bugger to fit and grade but we did it in the end by following the instructions with out deviating, the only slight problem is that is not too accurate at the b ottom range, but there is never any bouncing about of the needle.

Hope this helps BTW I have the same guage.

J