Fuel tank and oil ratio questions....

[petrolhead]

Having finished tarting up my FD-12 I thought I'd better give the old Mile Master pressure tank the once over. <br />I was pleased to discover that it still holds pressure and appears to pump just as it should, but I'll still strip and clean it to be sure. The tank however has a fair bit of rust and crud sloshing around in the bottom, and there's some surface rust on the inner walls, nothing serious but it needs to come off. <br />Firstly what's the best way to remove it, persuade my dear wife who's hands are slimmer than mine to get in there and clean it with a wire brush or wire wool, or is there a better (safer) way? And once removed what's the best way to keep it from rusting, some sort of tank treatment?<br />Second question concerns fuelil mix, everything I've read here and elsewhere says 24:1 for this year ('58), but on the tank it says one Quart to a 6 US Gallon tankful, or one Pint to one Gallon. Well whether we're talking US or Imperial measures that's 16:1, not 24:1!<br />Do I just have an older tank and should I ignore this? I don't really want to run on 16:1.

 

[funpilot]

Re: Fuel tank and oil ratio questions....

two cups to a pint, two pints to a quart, four quarts to a gallon.<br /><br />A cup is eight oz, which makes a quart 32 and a gallon 128.<br /><br />(6 x 128):32 is 768:32 = 24:1, so it appears that your tank agrees with your motor.<br /><br />One pint (16 oz) to one gallon is 128:16 = 8:1. Now that's a scary mix!<br /><br />I think you can safely run with modern oils almost any motor at 50:1 (or at a minimum 40:1), the oils dispearse so much better now days. Mercury told me as much back in 1985.<br /><br />Wish I had a good answer about your tank cleaning problem... <br /><br />Good luck.

 

[alcan]

Re: Fuel tank and oil ratio questions....

Hi Petrol<br />Buddy if you can con your wife into scrubbing tanks, you have got one nice lady there. there are lots of ways to get the rust out of these tanks. Most of the time the stuff you see on the bottom is rust colored varnish. Most of the rust is actually on the inside, top and sides, where you really can't see it. I like to use a product called Kreem, it is sold for motor cycle tanks. It uses and acid wash, then a seal coat. It is a two part process. I rarely use the seal coat on outboard tanks. I also make,buy brushes that will reach in the tank. Some brushes I will fit with plastic tube or stiff wire handles so I can bend them to go where needed. A toilet cleaning brush is one of my favorite.

 

[petrolhead]

Re: Fuel tank and oil ratio questions....

(6 x 128):32 is 768:32 = 24:1, so it appears that your tank agrees with your motor.<br /><br />Sorry, I still find US measures confusing!<br /><br />What I should have said is that the mix on the tank is one Quart to a 6 Gallon tankful, which as you say is 24:1, OR half a Pint (not one Pint, my mistake) to one Gallon which is 16:1<br />So the two mixes on the tank are different!

 

[JB]

Re: Fuel tank and oil ratio questions....

That's a 1958 engine, PH. Correct mix is 24:1, but 25:1 would be fine.<br /><br />That would be 40cc oil per liter of petrol, or 800cc oil to 20 liters in that 6USG tank.<br /><br />It wouldn't hurt to use 1 liter of oil and fill the tank.<br /><br />DO NOT let anyone talk you into using a 50:1 mix in that engine unless you don't want it any more.<br /><br />Good luck.

 

[alcan]

Re: Fuel tank and oil ratio questions....

Petrol, mix fuel at 24:1. Use 1 U.S. quart of oil to 6 U.S gals. That is 1 quart oil to one tank of gas. The math of the given ratio doesn't always equal the given amounts exactly. Some time you will read and amount as a 1/2pint to the gal or a quart to 6gals. This all means 24:1 in outboard terms. The people who originaly wrote the recomendations were trying to save operators from having to use a slide rule to figure out how much oil to add. So they rounded to the nearest common unit of measure available at the time. They always rounded to the fat side on the oil. The 1 quart to 6 gals should be concidered the minimum amount of oil in your case.

 

[jlehan]

Re: Fuel tank and oil ratio questions....

i would just add 1 liter of oil for 24 liters of fuel<br />the metric system is so much better<br />if uhavea 20 liter tank i would add 850 ml for a full tank

 

[petrolhead]

Re: Fuel tank and oil ratio questions....

jtl, now I'm sure of the correct ratio that's exactly what I'll be doing, petrol is sold in litres in the UK anyway, so to mix my fuel in imperial I'd have to convert it from metric in the first place!

 

[jlehan]

Re: Fuel tank and oil ratio questions....

im in canada and we use the metric system as well so i know where u re coming from!!!

 

[funpilot]

Re: Fuel tank and oil ratio questions....

With all due respect to JB, I ran a 63 Merc 45hp on a wooden boat for skiing and general fun (mostly at wide open throttle) every weekend and many times during the week at 1 pint to six gallons (approx 50 to one) for five years without a problem. In fact, Mercury (the factory people in Fon du lac, Wisconsin) told me specifically that my engine would run better even though they originally designed it for 25:1. They considered the dispergent properties of the oils that much improved. But... do what you think best. I liked the cleaner plugs, the easier starting and better wide open throttle response that came from the cleaner mix.<br /><br />JB has a lot of experience, and he may have more 'horror stories' than my one good experience, so I do defer to his judgment as well.

 

[mologus]

Re: Fuel tank and oil ratio questions....

If you have a way to rotate your gas tank. You can put bearings or BB's in it and start rotating the tank until it is clean. (do not rotate to fast, you will want it to slosh around in there).<br /><br />Rotating the tank, you could put it on a motorstand and start turning it. I have heard a small conrete mixer would work. Of course fasten tank securily.

 

[BillP]

Re: Fuel tank and oil ratio questions....

Weird but true...My uncle cleaned a badly rusted merc 6 gal boat tank by jacking his car up and strapping the tank to a rear wheel. He put rocks in the tank and let it idle in gear a few minutes. He said it came out sparkling clean. He's an antique engine collector. Those guys have ways to fix anything. They do stuff like pump grease into the spark plug holes to free frozen engines.

 

[JB]

Re: Fuel tank and oil ratio questions....

We are not talking about a 1963 Mercury, Funpilot, we are talking about a 1958 Johnson.<br /><br />OMC said 24:1, so 24:1 is what I recommend.

 

[funpilot]

Re: Fuel tank and oil ratio questions....

Thanks JB... I understand, and stand corrected!

 

[rickdb1boat]

Re: Fuel tank and oil ratio questions....

Paint mixer on a drill will work, too....

 

[petrolhead]

Re: Fuel tank and oil ratio questions....

Just noticed this post is attracting attention again, I've actually done the tank now and it was very successful.<br />I used a pillar drill with a flexi-drive, and a wire brush in the chuck, wearing a leather glove for safety I removed most of the rust from inside, I could just squeeze my hand in the tank to do it!<br />After that I blew out all the loose rust with an airline, poured a small tub of Hammerite Rust Remover gel inside and sealed the top with masking tape, sloshed it all around and let it stand half an hour. After which I removed the tape and agitated the gel with a brush a couple of times, letting it stand 15 minutes or so in between.<br />Flushed it with water and dried it out, now there's not a trace of rust, just some very light pitting where it used to be. I did think I'd coat the inside with epoxy like the motorcycle restoration guys use, but decided not to. As long as it's not left with old fuel in it for ages there's no reason why it should rust again.

 

[alcan]

Re: Fuel tank and oil ratio questions....

Good Job Petrol, still a nasty job isn't it. I didn't think you were honery enough to ask your wife to do it. As you all say, cheers.

 

[petrolhead]

Re: Fuel tank and oil ratio questions....

Not the most pleasant job I've ever done alcan, but certainly not the worst, I've been up to my elbows in far nastier things than rust before! <br />I chickened out of asking the wife, I value my marriage/life more than a fuel tank.

 

[Hooty]

Re: Fuel tank and oil ratio questions....

The method with the rocks (we call it pea gravel) works good too and it's not near az messy.<br /><br />c/6<br />Hooty