Saving Old Seagulls

I'm currently fiddling with getting a Seagull running on 'green' fuel.

Initial experiments with spirit stove fuel alcohol (clear meths:- 90%+ ethanol, 3% methanol, the rest denaturants and water) mixed 25:1 with Castrol R30 oil (made from pure castor oil so theoretically biodegradable) are promising though the approximately 9% higher density was causing problems with a lower fuel level and thus leaning out the mixture.

Initially starting was extremely difficult but backing the needle out a couple of turns, and adding approx 1% acetone to make it more volatile, cured that. It 'bogged' down if the throttle was opened too far due to the mixture leaning out and I plan to add a sheet metal weight on top of the float to get the level the same as when using petrol to cure that. Tickling the carb till it dripped and continuing to tickle while running allowed the needle to be returned to its 'regular' position and still start it easier.

Next I need to do extensive tank testing then possibly a sea trial.

Does anyone else have experience using castor oil and alcohol (or methanol) or even E85 gasolene in a seagull? It could save me a lot of time if someone has already pioneered this!

Ian your going to need a way bigger jet, as you will have at least double the fuel consumption, so the gravity fuel feed via the needle valve might also be a little slow.
It also might be having trouble getting enough heat into the fuel to vapourise it properly, try restricting the tell tale.

Make sure there is no rubber in the fuel system, as I think that mix might well damage it.

This will be interesting!

http://www.smokemup.com/tech/fuels.php

Yes, you are right, definitely need to re-jet. I think I'll also put the 10:1 needle back in to get it richer at the low end.

I may not even need to 'weight' the float.

Anyone in the UK got a ****ed up jet for a Villiers carb on a 40 plus and willing to donate it to science? I can send a stamped SAE so it can be posted. Thread needs to be OK, jet can be totally b*****ed as I can solder that up, it doesn't matter if you used mole-grips to undo it, but obviously *try* not to do that!

Just thinking: If one was to rejet for nitromethane, I wonder if a forty plus could handle a 5 blade hydrofan off a Century. Might be worth looking at if one is into racing as its much coarser pitch. The head would need skimming as the compression would need to be a good bit higher.

There are 2 different sizes of Villiers carbs,

The 40 series version at about 3/8",
& the 102cc version at about 1/2",

It's a reasonable assumption that the 102cc version should flow a greater amount of fuel than the 64cc one.

I haven't studied these carbs, as I've never used one for racing, so these sizes are only a rough measurement.

Piston cooling in a Seagull is mostly a function of fuel evaporation on the under side, so you might well have to increase the piston temperature to give your fuel air mix a suit consistancy for efficient combustion.
The easyiest way to do that is raise the top end compression ratio, I'd guess your going to need at least 140lbs, so you might have to skim the top end of the cylinder & remove the insulating paper gasket between the cylinder & the crankcase, which will move the piston closer to the head by further 10 thou.
If you do that your going to make all the bearings in the powerhead work quite a bit harder, so start with a real good crank & crankcase.

How Interesting!

I had to look up....


de·na·ture
   
1.to deprive (something) of its natural character, properties, etc.
2.to render (any of various alcohols) unfit for drinking by adding an unwholesome substance that does not alter usefulness for other purposes.
3.Biochemistry. to treat (a protein or the like) by chemical or physical means so as to alter its original state.
4.to make (fissionable material) unsuitable for use in an atomic weapon by mixing it with unfissionable material.

—Related forms
de·na·tur·ant, noun
de·na·tur·a·tion, noun

So, obviously you can no longer drink it then. Bugger!

Meths/stove fuel is no go for compressed ignition, it will just try to blow itself out so I reckon the only thing really burning/expanding initially is the Methanol which, in turn, will supply enough energy for the Meths to go "pop".

I suggest chuck the stove fuel and go buy some Methanol racing fuel instead. It has some additives that make it suitible for internal combustion including some anti knock compound.

Then, re jet way up, change the slide cut out considerably and make fuel lines and tap as big internally as possible.

Be prepared to follow the rest of the previous advice and observations as well as working out what the new ignition advance is going to be by making a handle for the base plate to swing on. You will probably have one setting for starting and another for flat out running.

It will end up being an alcohol engine in the end so do not think for a second that it will operate over an extended RPM range. It will, when finished, run very cold which may upset bearing wear to some extent.

Good Link:

http://www.turbofast.com.au/racefuel2.html

Methanol and R30 are both hydroscopic so always use fresh fuel and always use proper oil to fog your internals after every use else........internal rust. Also, forget just mixing to a ratio as the whole thing has been thrown out of whack. Just enough oil so that when running flat out some blue/dark grey smoke is just noticeable.

Heat range of plug will be the old fashion way, by eye.........aye?

It will smell nice as well!

Go for it Mate!

Regards

B

Thanks for all the comments, help and suggestions so far.
It looks like a racing alcohol seagull would be a fully custom engine, with a modified carb, block, head and piston, + variable timing but a bio-ethanol 'green' seagull might just need a tweaked carb and an extra 'dimple' in the top bearing housing to allow the timing to be easily reset for ethanol.

It looks like a small percentage of acetone will not only reduce the flashpoint to something more in line with that of petrol but will also significantly increase the water tolerance of the fuel that can otherwise be at risk of the oil separating.

There is some useful info here:

http://www.journeytoforever.org/biofuel ... l_ToC.html

I'm off sailing for a week or so and all experiments are on hold till I'm back.

Hello there, Ian.

Now that it's been a while, might I ask you if you've seen any fuel system decomposition from playing with your alcohol fuels, namely Ethanol-based ones?

Clearly, these engines' hoses and carb parts weren't made to withstand high percentages of alcohol but if they're holding up, that would be good news.


Thanks.

- Ted

Perhaps I can help I'm a yacht designer and a bio-fuels proponent. Because ethanol/methanol is very hydroscopic in fact by distillation you cannot get over 96.6% pure, you'll always have some water dissolved in your fuel, using it to fuel an outboard would be very hard almost impossible because you must be close to water.
But this is a problem that must be solved. Most US states and the UK sell a blend of Gas or Petrol that has 5% plus of ethanol and water displaces the ethanol. Then the free ethanol rots the hoses. What you can do is mix 5% bio diesel into the ethanol. The bio-diesel is also a solvent and replaces the water.

OK, are you suggesting that we mix in some biodiesel @ 5% of the amount of Ethanol we think is in the fuel, or, should we mix it up so our gas tank contains 5% biodiesel?

Once clarified, & when spring wanders around, I'll have to try this; I assume it's the presence of microbes found in bio-diesel that is the factor, vs. pure petroleum diesel fuel being used?

Thanks for the input!


- Ted

Ian

Well done on doing a bit of research & experimentation. So, the objective here is a 'green' fuel eh

Firstly
Suggest re-jetting the carb, as, opposed to adjusting the float level. Ideally you want the fuel level in the float bowl a specific measure below the jet discharge. The carb is likely to get upset if this measure changes too much

Secondly
Perhaps a little caution with the castor oil. It's a double edged sword. I'll explain.

Your engine needs to hold lube oil on the surface of the bore & the piston. The usual mechanism on the bore are the tiny voids of a cross hatched hone pattern imparted into the walls. Note, your standard seagull has this oil holding mechanism in the bore.

The usual mechanism on a piston are the tiny voids of either oil grooving machined into the skirt, or, surface hatching of the skirt. Note, your standard seagull has neither of these oil holding mechanisms on the piston, rather it uses it's (rather limited) surface finish.

When you use castor oil, the combustion process quickly converts it into a residue commonly called varnish (or gum). This varnish quickly fills up the tiny voids or surface finish that holds the lube oil. Result can be catastrophic failure. Back in the pre-historic days of castor oil on the bike track, it was common practice to ride the straights with your hand on the clutch in readiness of your engine seizing prior to the race end. To effectively remove the varnish, it's a case of dismantling & harsh mechanical abrasion. Castor might be cheap & avaliable, but, there's a price to pay. Make no doubt, the piper will be paid. Maybe look into an alternative bio oil to castor.

Having said all that, castor oil smells nice. Modern synthetics smell awful, like burning plastics. yuk!

Hope I've not put you off the idea of 'green' fuel

Rex

just curious but I thought ethanol based fuels were a big no no for marine based use due to its moisture attracting ability,

Yes, alcohol based fuels are hygroscopic.

This can lead to corrosion & other issues

However, surely what we use them for is still up to the individual. (unless the western world has gone under communist dictation) Ha Ha

chris wrote:just curious but I thought ethanol based fuels were a big no no for marine based use due to its moisture attracting ability,

Yes, in theory, avoiding alcohol-laced fuel would be great. Just let us know where we can get some fuel without the ethanol in it

The chief alternative of which I'm aware, is aviation fuel. 100 octane, a little lead, and it doesn't stink quite so much as car fuel anyway (to me at least). Ethanol has created quite a problem for our larger-boat owners who can't just flush the tank every trip or two.

My solution to date, is to rotate supply quite liberally. By keeping only a gallon or so of "gasohol"/oil mixed at any time, one can hopefully use most of that within a month and then dump the remains into the family car, then mix up some fresh fuel. Just one answer, not necessarily the best answer. It sure beats rowing.

If using bio-diesel as a water-absorbing agent works, that would be a fine thing.


-ted

... in the meantime...

I’ve just completed a project: converting a smoky, smelly Century 100 into a clean-running, alcohol-fuelled “vaping” Century 100.

The issues I wanted to tackle:
Petrol smell in the car when transporting or storing the engine

Two-stroke smoke on the water while the engine is running

Seeping gear oil from the bottom end (at any opportunity)

Oil in and on the water during start-up, running, or engine tilting

The gear oil issue was simply resolved by filling the gear case and letting any excess oil run out while the engine was upright before sealing the filler. The thick water-in-oil / oil-in-water emulsion (gearbox “mayonnaise”) is so viscous that it doesn’t seep out at all.

For the other issues, I aimed to find a fuel and two-stroke oil that are as biodegradable as possible and do not harm the Seagull. These also had to be readily available.

Fuel: Bioethanol stove fuel (available across the UK) or E85 (available elsewhere)

Oil: Silkolene PRO KR2 (UK-made), or any alcohol-fuel-compatible two-stroke oil such as Motul Micro or Klotz Super Techniplate

Why this doesn’t work with the stock carburettor:
A) Ethanol has a significantly lower energy content per volume than petrol, so the main jet is too small
B) The evaporating ethanol cools the intake air (which is great for engine temps) but makes cold starts difficult

To address point B, I now use a mixture of 80% bioethanol and 20% petroleum ether (boiling range 40–60°C). It now starts very easily.

To address point A, I replaced the centrepiece (the long brass tube in the middle of the Villiers carburettor) with a larger one. I went from a 7J to an 8J and drilled out the:

Main jet (lower part) to 0.95 mm

Needle jet (upper part) to 2.1 mm

I kept the original centrepiece unmodified so I can revert to petrol in future and undo my modifications if needed.

Final Fuel Mix
(for my setup only)
75 ml alcohol-compatible two-stroke oil (e.g. Silkolene PRO KR2)

800 ml bioethanol

200 ml petroleum ether (40–60°C boiling range)

Jet Sizes (Villiers Junior Carb V508C/1 on a Century 100):
2.1 mm (needle jet, top)

0.95 mm (main jet, bottom)

Note: These jet sizes are only correct for my specific setup.

Cold Starting Tip
Rope-starting from cold can be made easier by super-flooding the engine — two lazy pulls with your hand over the air intake, followed by a strong pull.

Final Result
The engine now runs very well. It vapes rather than smokes, and it doesn’t leave a petrol stink in the car (just a faint boozy aroma). When the fuel hits the water, it completely dissolves. The oil emulsifies in the water and, since it’s designed for ethanol fuels, is more easily metabolised by microorganisms. The unburned fuel — inevitable with two-strokes — is either biodegradable (ethanol component) or evaporates rapidly (petroleum ether component).