Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Fuel Tank size

Tried a little test on our new Plus Four. The handbook says the tank holds 43 litres and that a warning light will come on when approximately 6 litres remain. We carried on for another 40 miles after this point, approx 4.5 litres, which meant we should have 1.5 litres left. The gauge was now right on the empty mark and we dare not go any further as there is a warning in the handbook to not let the vehicle run completely out of fuel as this may damage the engine and other components.

We thought we must have been running on fresh air at this point and were somewhat baffled when we pulled into a service station and only managed to squeeze in 31.03 litres rather than the 41.5 litres we were expecting.

Is the size of the tank overstated or do we have a duff one?

Sir P

Morgan fuel gages are at best vague....

Ive measured a +4 tank at 43 Litres...

They all do that sir. My Roadster gauge is useless. I use the oddometer to judge when to fill

Whilst you might not have been able to fill it up as much as you estimated, you car is probably doing more MPG than you first thought. I find my fuel gauge can drop suddenly within a few miles, then as soon as I find a constant speed it rises again. At best the fuel gauge is an indication of some petrol in the tank, often beyond that hopeful note of optimism , I tend to rely more on the miles travelled since last fill up and my conservation MPG estimate as my more reliable gauge of remaining fuel, as I don't need the onset of remaining range anxiety.

On that particular test we had done 280 miles and used 31.03 litres (= 6.83 gallons) which equates to 41.02mpg

If as you say the fuel gauge is somewhat iffy that would mean I could have gone for a further 100 miles (43litres = 9.46 gallons @ 40 mpg = 380 miles).

Would you have carried on with the fuel warning light flashing and the fuel gauge showing empty for a further 100 miles. Surely the fuel gauge can't be that far out.

Interestingly on our previous Morgan a 3.7 Roadster the fuel gauge and miles left indicator were extremely accurate, I would have trusted them with my life!

Which is fine if you know how much the tank holds, that's what I am trying to find out

I thought you just did or did you not note the mileage? I just fill every 200-220 miles as the avg mpg is around 29. Yours should be far higher of course.

I guess you are after the real end mileage possible, I just don't take the risk and start looking after 200 miles.

I do as John does and fill up at 200 miles knowing I probably have another 50 miles in hand at 23mpg with my 1999 Plus 8 - as the fuel tanks appear to vary if you really must know the capacity fill it up and pump it out using a small 12 volt pump and 5 gallon drums it will be the only way to know.

Most of us run on the odometer method I think you'll find.

Take out the spare wheel, accurately measure the tank and cube up it's volume, however as some have found you can't always get a Morgan tank properly full due to venting issues as you pump petrol in

If he has one Jon... Plus Four..