Working on Gas Tank, ?s - Larson Manta 175

[Woodbinekeith]

It has a metal tank about 40" x 24" X 8" high. Guessing it holds about 12-15 gals and probably original - 1977. It had been out on the water with previous owner about 6 weeks ago but don't know if he used the tank or a portable carry-on. At any rate, I do want do do something about the gas tank.

Tank looks good from outside, fittings seem to be o.k., was used with a 2 cycle mix-the fuel/oil and doesn't seem to have much gas in it. I'm going now with a Merc oil inject. It has 2" wood lathes screwed to whatever is underneath on both ends and fit over the metal edge of the tank to hold it in place. This looks like the only way it is secured.

I could pull the tank, check out all the fittings, and give it a good cleaning (a really good previous thread on this). Not sure if I would have to take the tank out to do this - but how does on know for sure it is clean if it isn't removed?

I could pull the tank and just send it off to boat heaven or sell it. Replacement would be a 25L carry on.

I could just leave the tank on board, drain it, and set a new carry-on right on the top as there is room to do this. Probably not a good idea but it would be the least problematic.

Any thoughts - maybe another option or two

 

[Beefer]

Re: Working on Gas Tank, ?s - Larson Manta 175

First of all, those dimension equate to a 40 gallon tank (39.2175gallons for the purists).

I'm not really sure why you want to get rid of the tank. Is it because of the oil mix the previous owner was running in it? If so, and the tank is empty, the ratio of gas/oil won't be compromised enough (I think) to make a noticeable difference. If it's not leaking, and seems to be in good overall condition, I can't see a reason to decrease your fuel capacity by 75% (25L = 10gal +/-), and your topside roominess.

Why not contact the previous owner, and ask him which way he ran it last time out (fuel tank or carry on).

 

[Woodbinekeith]

Re: Working on Gas Tank, ?s - Larson Manta 175

Appreciate your thoughts, Beefer. I just want to be sure I have clean gas going into my new-to-me motor - 1990 90 HP Merc. Yes, it would be a shame to reduce the fuel cap this much.

Tipped the bow up a bit and just siphoned off the gas. It was about 7 gals - looked very clear and smelled good so will use it in my lawn mower. Surprisingly, no bits and pieces of garbage came out. Took off the motor fitting from the hose, used the bulb to get it going, and it worked very well.

Tomorrow I will get a couple gallons of denatured alcohol (methyl hydrate). A former poster suggested to leave it 48 hours and then run it through and I will do this, likely twice. Voila - mix it with 65% per cent water and will have lots of windshield washer.

 

[Fed]

Re: Working on Gas Tank, ?s - Larson Manta 175

I'd keep the old tank too.

You might want to check your numbers Beefer.
Check this out I use it all the time.
http://joshmadison.com/software/convert-for-windows/
(40 * 24 * 8) / 231 = 33.2467532
25 / 3.785412 = 6.60430093
That 90HP carby Merc won't go far on 6.6 Gallons

 

[Beefer]

Re: Working on Gas Tank, ?s - Larson Manta 175

I'd keep the old tank too.

You might want to check your numbers Beefer.
Check this out I use it all the time.
http://joshmadison.com/software/convert-for-windows/
(40 * 24 * 8) / 231 = 33.2467532
25 / 3.785412 = 6.60430093
That 90HP carby Merc won't go far on 6.6 Gallons

Here are the online calculators I used -

http://calculator-converter.com/l_t..._gallon_conversion_calculator_chart_table.php

and

http://www.dep.state.pa.us/dep/deputate/waterops/redesign/calculators/volcalchtm.htm

You're right on both. I must have misread or entering in something wrong when I did L to Gal, as I also come up with 6.6g. The volume calcutator asked for the dimensions in feet, and I must have converted those difficult (lol) inches incorrectly. (I used 3.5 ft x 2ft x .75ft, when it's really 3.3333' x 2' x .66667') I must've been tired. I'm glad you caught that. From here on out, I promise I will stop doing math after 8pm after working a full day and then boating. :redface: