One of the things on my project list this year was to get rid of some old fuel that was worrying me. I had visions of the crud on the bottom of my tank churning up and killing the engine at the worst possible moment. So, I had the tank pumped out and hand-scrubbed clean. Two inspection plates were cut, one on each side of the baffle in order to clean the tank. My sensor was also a bit glitchy, so I talked to the fuel tank guy about different tank sensors. He suggested installing a simple 3/8" capped plug on top of the tank, which he did. Now, I can just use a 1/4" dowel to measure the fuel. I took measurements while re-fueling and it's about 1/2" per gallon. I feel much more secure being able to physically measure the fuel.

Mike

Caution here, Mike and Ron...the fuel tanks on the Mk I and the Mk II are completely different shape, volume and location.

One of the things on my list is to install a tee at the outlet and inlet of my tank. With some clear fuel resistant tubing it would give a sight glass to show the fuel level.

There seems to be a recurring "need" to know the fuel level in tanks. One approach is to know your fuel consumption. You already have an hour meter and know the tank volume in gallons. Doing the math is simple. Over the course of 13 years I have carefully recorded my fuel use, which for our M25 is slightly less than 1/2 gallon an hour of running time. Our fuel gauge or sender bit the dust 12 years ago. 23 gallon tank, every twenty hours I add 10 gallons. Not so hard. Before I sell the boat (not likely!!!) I'll fix it. M35 engines reportedly use closer to 1 gallon an hour.

Because of the uneven dimensions of the tank, the fuel gauges aren't linear anyway.

I replaced my tank level float with a small ball valve on top of the tank so I can use an accurate sounding stick. I wrote about that a couple of years ago. I do not know if that can be done on a MKII
Hans Treu
Hull #849 / 1988

[QUOTE=LCBrandt;9500]Caution here, Mike and Ron...the fuel tanks on the Mk I and the Mk II are completely different shape, volume and location.[/QUOTE]

Ahh, you're right Larry. If I recall now, I think I saw somewhere that the MK II fuel tank is tucked away in the aft cabin somewhere. Perhaps my dipstick wouldn't work there. Yet another reason to love the MK I. LOL

Mike

Picking up on Stu's comment about the overall average fuel usage, for the first several years we owned our 1999 model with the M35B engine, we saw an average of 0.55 gal/hr. I thought that was exceptionally good, BUT I failed to consider that 80% of the hours the engine was running was to motor at a modest speed out of our canal system and into open water. We rarely went out unless there was sailing wind, so most of our engine time was NOT pushing the hull at 5-6 kts in seas.

When we finally took our 4 month cruise to the Keys and Bahamas and had to motor extensively at times, I found that pushing into a strong head sea at 5 kts took closer to 0.9 gal/hr and that a good average for motoring in average seas at close to 6 kts was more like 0.75 gal/hr.

My point is to be careful with overall averages, as I am sure Stu is well aware.

Thanks Duane, good points.

Mike