[97 Z222]

According to my manual, I should have a 50 US gal fuel tank or 187 litres. Last week my fuel gauge was reading empty, so I went over to the marina and filled up. I was surprised when it only took 108 litres to fill up. This ment that I should have 79 litres remaining. The next day when I got down to empty again, I kept boating for about an hour and a half when the boat ran out fuel. I should have had lots of fuel left. So after an embaracing tow back to shore, I put 20 litres in by jerry can and drove over to the marina and to my surprise, the pump reads 117 litres after the fuel spills out the vent line. Total fuel put in is 137 litres. Where is the other 50 litres of fuel? Does anyone know what the sending unit looks like in the tank? Has anyone else had this problem? Is it possible that I didn't get a 50 gal tank?

[WetWilly]

Hi 97 Z222,

According to the 97 Mariah brochure, your Shabah has a 49 gallon tank or 223L, but we all know that 49 gal is only about 185L.

Now if your Shabah was perfectly level, you might get all 185L into the tank, but as most of our boats sit low in the stern when at rest in the water, and if I remember correctly, the vent tube is near the fuel gauge and they normally sit at the back of the tank.

So as the fuel level in the tank rises, it will reach the vent passage before filling completely up so there will always be an air pocket in the tank.

So its how low your stern is that will determine how much fuel you can actually put in.

If you have a trailer, go to the gas station when your Shabah’s nearly empty, put a small level on the floor to ensure the tank is level or slightly down towards the bow and see how much fuel you’re able to pump in. Remember to slow the fill when you get over 100L as there will be a lot of splashing in the tank and some of it can get pushed out the vent.

Good luck,
WetWilly

[Z 202]

The fuel capacity should be written on a label on the top of the tank. Flip the back seat forward, and open the little hatch in the floor just forward of the engine. It should reveal the gas tank, sender connections and the label. You might also want to check the sender's resistance. On the '95 202 it reads between 10 ohms (full) to 250 ohms (empty).

[180diablo]

Just going by personal experience here...

My boat holds approx 23gal / 87L and I have yet to fill it to the brim. I normally fill up a 25L (jerry can) on Friday or Saturday and either get a whole weekend out of it or stop by a gas station (on the road) for another 25L on Sunday. Purely dependant on engine use of course.

Now I know everyone boats differently and we all know the 3.0L sips fuel vs a 7.4L. But, I don't really have a need to keep the fuel tank completely topped up at all times. Take what I need, use it, replace when needed. On a 6hr trip we did take along an 10L jerry "just in case". Which we did end up using.

As Z202 mentioned, pull back the seat and find your tank and inspect the label on top of the tank. Mine was there and plenty easy to read.

[ShabahZ280]

Originally Posted by 180diablo

... we all know the 3.0L sips fuel vs a 7.4L...

Jeez, don't drive the knife any deeper or anything!

This year's definitely been the most expensive boating year so far, but it's worth it, especially on a Mariah!

Mariah made their own fuel tanks for each and every model, they were molded to fit the open areas. Mine has a 56 gallon tank, but for some reason won't ever hit a true fillup, even from empty. I think it's a pretty common occurrence, plus figure in the size of the fuel sender and everything too, that would take up some space in the tank as well. Also factor in things like temperature too, gas expands at higher temps. I've filled the boat up, left it out in the heat, and later found a fuel trail from the vent. There's all kinds of variables that might explain the situation for you.

[lomitabob]

An additional note...in my Z250 if I run out of gas it takes 10 gal before the fuel pickup will pickup enough to start the 7.4 MPI engine. I found this out the hard way!

[WetWilly]

Looks like you're going to need two jerry cans just to get restarted and a third to get back...

[97 Z222]

Thanks for the replies. Just got back from a week of boating at Canum Lake in the interior of British Columbia. Well, I didn't run out of fuel this week. For now I am just treating the tank like it is only 100 litres until I get my fall winterizing and check up with the mechanic. I'll have him check it out then. Still a head scratcher though. I think that wet willy might be on to something with the level of the tank when filling in the water. I'm going to have to try a level land fill up and see if that makes a difference.

[z275st]

Just got back from the annual Ohio River/Kentucky Lake run. 23 guys and 5 boats.
Filled up the tank with 115gal. If your Diablo 180 sips gas ,I guess mine guzzles it like a college kid drinks cheep beer on spring break! I get 2.2mi/gal.

[ShabahZ280]

Originally Posted by z275st

I get 2.2mi/gal.

How are you able to calculate this, with the Smartcraft? What RPM and speed were you running at? Man that's so cool, I'd love to find out where my optimum MPG is. (besides idle speed)