fuel 25 /1 whats best way to measure

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shantymanuk
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fuel 25 /1 whats best way to measure

Post by shantymanuk »

Hi all i know it sounds daft but whats the best way to measure two stroke oil to a gallon of fuel ,, ie how much to a gallon for 25 /1 mixture , im sure i got it wrong last time as more smoke than a bonfire night ,and had to keep adding fuel to the mix god knows what the mixture was in the end
old boats look naked without a seagull
philj
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Post by philj »

Hi,
most bottles show the ratio's on them these days but it's about 200mls,
or 2 1/4" of oil in a standard dairy crest milk bottle! I marked one up with tape for ease of use. It's not that critical, but if you don't make smoke then it's not enough. Always mix it in a can never in the tank and always add the oil to the petrol. Give it a good shake and away you go.
rehards
Phil
Vic
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Post by Vic »

A hell of a lot easier to work in litres and make the fuel mix 4%.
Then it is 40cm³ of oil to every litre of petrol.

I use a conical measure for measuring the oil and a graduated plastic jug for measuring the petrol when necessary. Unnecessarily precise but very convenient

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Last edited by Vic on Sat Dec 20, 2008 8:38 pm, edited 1 time in total.
pistnbroke
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Post by pistnbroke »

you can get a calibrated plastic bottle about 100mm high from most boat engine suppliers /Mercury /yamaha etc . It has scales for 10:1 25:1 and 50 :1 you look how mech petrol you need to mix say 5 litre and then fill up the that line in the bottle ...then tip it in with your petrol ...or make your own 10 liter of petrol add 1 litre of oil ...etc

can send you one if you desperate ..wife comming to uk in a couple of weeks they are about 2 quid

Of course if you had a Briggs and Stratton you would not need any oil only in the sump !!!!
Last edited by pistnbroke on Sat Jan 03, 2009 7:14 am, edited 1 time in total.
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timberman2004
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Post by timberman2004 »

Ahhh really easily done

STIHL chainsaw / strimmer dealers sell standardised 2 stroke oil in little twist off top, plastic bottle-ettes...exact amount for 50:1 mix

empty,& throw away the oil (or get an empty one from a mate ) cut off the bulbous top bit and theres your measure

thus 2 little bottlefulls per 5 litres you're at 25:1
Neal...errrr... an ON, OP, 2xSD, F, 3xSJP, LLS, 2xFV, FVP, FPC, CPC WPCL, WSC, and a few eggs hatching, hopefully
mick r
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Post by mick r »

I work in pints, (as seagull intended), those guys at poole would never have stood for this metric crap.
1 pint of oil, 24 pints (3 gallons) of petrol. :lol:

As far as I'm concerned, those people in Brussels can stick their litres "where the sun don't shine" !! :oops:
Vic
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Post by Vic »

1 pint of oil, 24 pints (3 gallons) of petrol
Maybe I suppose but I prefer to mix my fuel as I need it. Never ever going to need 3 gallons at a time (dont have a 3 gallon can any way) Never seen the oil in pint bottles, been in litres ever since I've been buying it!

I see though how much more convenient it is to work in gallons. That works out at 0.54 of a litre bottle of oil into 0.6 of a 5 gallon can of petrol.

Bet you still buy things in pounds shillings and pence too.

What have brussels got to do with it. We only buy those at Xmas.

To answer the original question though the correct volume of oil for a gallon of fuel is 180cm³ (assuming thats an Imperial gallons not the short measure the yanks give you) or 0.32 pint or 1.28 gills
TrueBlue
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Location: Me: Sussex, Boat(s) mid Thames

(More) Accurate measurements

Post by TrueBlue »

Vic(s) said come here for help, and I noticed this thread while attempting a search for my problem.....

I use round spice jars kindly donated (ex rubbish bin) by SWMBO.
The type I'm thinking of (of which I'm thinking) are 4 1/2" tall by 1 3/4" wide. There is a crimp near the to and filling to this mark is exactly 50 ccs:

As the bottle is tall and thin its fairly easy to guess smaller quantities - e.g. 40cc for 25:1.

For the fuel measure I use 2 or 4 pint plastic milk "bottles". They are all graduated in foreign as well as "proper" units.
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Charles uk
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Post by Charles uk »

If you look at a pre war petrol tank, the fuel mix quantities were given in Imperial & Metric measures.
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John1952
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Fuel 25-1

Post by John1952 »

I measure two of these into a gallon can. (Not this oil) !! just useing the bottle to measure with, (easy peasy) keep it simple!
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Charles uk
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Post by Charles uk »

Gentlemen I'm a little concerned that all the 2 stroke oils your talking about are for air cooled engines.
I suggest that you start your Seagull let it run for 10 minutes in your test tank & then place your hand on the cylinder, then try doing the same with anything you have that's air cooled, that hurt didn't it?

This illustrates my point, air cooled 2 stroke oil is designed to run in a much hotter environment so is more viscous at seagull temperatures, Seagull oil & all the marine equivalents are designed to run on relatively cool surfaces, like the ones in your outboard motor.

It's quite possible that aircooled 2 stroke oils, might be better in a very tired old Seagull with slack bearings & worn rings, but if you treasure your Seagulls why not try an oil made for the right purpose!

If you've ever tried to restore a Seagull, you will understand how cheap oil is in comparison to cylinders, pistons/rings & bearings, so saving a few pence in oil consumption might be a false economy.
A gloop too much oil never hurt a seagull whereas too little lube might.
Vic
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Post by Vic »

that all the 2 stroke oils your talking about are for air cooled engines
I think people are talking about using the containers that air cooled engine oil has come in as convenient measures , not using the oil that was in them.

BUT, but, but all the oils listed in the operating instructions for my Seagulls are oils for 2 stroke air cooled motor cycle engines.! They even say that you can use a non-detergent SAE 30 oil (Did that for a spell about 30 years ago and I think the smoke is still hanging around Portsmouth harbour)

I do now use a TCW-3 oil but having converted the Seagulls to 25:1 from their original 10:1 I rather worry that using a thinner oil as well they are now being under lubed.

IIRC there is not a huge difference in viscosity between air cooled engine oil and water cooled engine oil. I compared them in the laboratory once but these days the figures can be found on the internet.

PS reduced that big picture of mine to a clickable thumbnail. Forum now fits the screen. Sorry about that
Ian Malcolm
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Post by Ian Malcolm »

Take a perfectly clean and oil free on the outside, translucent plastic can, RED is good as you probably dont own anything that needs leaded petrol, and initially fill it 1 litre at a time on a level surface (measuring jug or *very* friendly garage, and mark the end *away* from the filler with the level for each litre CLEARLY with a permanent marker. It will probably take up to 6 litres for mixing purposes so mark it all the way, if you've got a Seagull to fill straight away but don't store it filled over 5 for safety.
Spray a light mist of fuel resistant lacquer over the markings and let dry thouroughly

Use the measuring jug from the chandler's preferably the one with the markings *MOLDED* in. (the printed ones markings wash off with petrol). If it doesn't do 25:1 double the 50:1. Make sure it can be read in litres of fuel. Or you can calibrate a straight sided bottle. Redex ones are quite nice. Very useful to have enough oil for 6 litres with you if there is any chance you'll be buying fuel on the water or beaching and walking to a gaarage somewhere. :-)

Its very easy even if you need to top off the can. Just measure the oil you need for the number of litres you are filling, and, making sure there is at least a litre of fuel in the bottom of the can, dump it into the filter funnel while pouring the fuel in. (This will actually give 24:1 if you are measuring by the markings you made but that's near enough. You can always allow a smidgen more oil.)

At the garage, I still use the filter funnel but watch the pump gauge which of course will give me a 25:1 mix. If you are doing a part can, estimate any part litres and its easy enough to get it closer than a Seagull requires.

*ALWAYS* use a filter funnel, you should see the crap that comes out of the tanks at some garages and you *dont* want that in your can or it will end up in your Seagull tank when filling afloat when its too rough to use the funnel.

As to mower oil, It will do no harm occasionally but I wouldn't want to run it every tank as there is a very small chance it may have additives that can cause plug fouling at the lower temperature or even cause corrosion which the old SAE30 didn't have. It wont be a problem to use up a litre or two though. Scooter oil has more additives but I had no problems with using up a couple of litres I'd picked up cheap.
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Collector Inspector
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Post by Collector Inspector »

25:1

Does not matter what units you use really. could be "Cans of Beer" actually!

One can of beer brand X to 25 cans of beer Brand Y is WOW! 25:1

One red potato to 25 white ones is also WOW 25:1

OK, lets talk Australian C-Powa. 102cc at five horse, 1952 Navy Spec (RAN) and it uses SAE 50 straight mix. See pics.

I have these running 25:1 (Modern Outboard TCW 3 Blah Oils) now with no changes to jetting.

Reed valve induction and full bearing crankshaft with seals good for 6500 RPM. Yeh, they hum along like a rotary. Interestingly, each piston is hand cut for the induction timing. Really cool that!. Piston matched to sleeve per engine. I have five and they are all different (pistons) but match their barels within 1 degree of induction start.

Make it Camo as Seagull and I would win ANY Race......................

Love this stuff, keep it coming, best wishes for the new year 2009.

Regards

C.I.



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Charles uk
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Post by Charles uk »

Almost identical to a Seagull 5R except the 5R has a steel needle roller con rod with a removable big end pin.

The reeds control the induction timing , the hand cut piston can only affect the transfer timing on the top surface of the piston, the cut out will only ease access to the shortened transfer port, that was used to increase crankcase compression, reed performance & piston cooling.

Looks like they suffer the same problems as the 5R, water corrosion on the drive end of the crank, destroying the oilseal, then the bottom bearing , then the crank!

Why didn't they fit a stainless collar for the bottom oil seal like I'm forced to do on 5R cranks suffering from lack of maintainence, it's not like you aussie's are spoilt by an excess of fresh water to play in.

This looks like a well engineered upgrade to the seagull style design, I assume they are running some cooling water back down the leg.
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