4 Stroke engine Fuel Modification

[YT2095]

it would seem that Di-Ethyl Ether (ether) as used in "Cold Start" for engines is perfectly soluble in petrol/gasoline also.

 

now since this is used in engines primarily to be sprayed directly intho the Air intake of the carbs to help start the engine on a cold day (rather than use the Choke, it says not to when using this stuff), what if it were mixed directly into the Fuel instead?

 

for some reason I`ve done all I can with this new engine, but when it`s even a LITTLE BIT cold, it`s a real b!tch to start

it`s great when it`s been running for about 5 mins, but requires several re-starts to get to that point.

 

could making the actualy Fuel itself more "Flamable/volatile" preclude this problem?

[doG]

It seems to me that this would lower the octane of the fuel causing a knock at normal operating temperatures from possible precombustion.

[YT2095]

but surely UPing the octane would make the problem worse for starting it?

there needs to be a happy medium somewhere, and I`m not on about chucking in 10`s os ml of this stuff, maybe just a fer per litre.

I`m really open to all reasonable sugestions here

[doG]

I have seen a dispenser mechanism on trucks before where a canister of starting fluid was stored in the dispenser that was operated as needed from a button on the dash. That may fit your needs if you can find one.

[insane_alien]

if its cold you want to increase the volatility(is that even a word)of the fuel to get it to ignite properly. diethylether should do it if you nix it in with the fuel. even adding some straight chained alkanes under octane should do it. maybe something like 100 ml of hexane to 1 litre of fuel.

[entwined]

Why not have a mechanic look at the automatic choke on the engine?

 

By the sound of your OP, that is whay ails your car.

[YT2095]

it`s not a car, it`s a 1977 Briggs & Stratton engine currently mounted to a board, single piston, horizontal shaft, and a large magneto flywheel is the only electrics on the thing, it`s a pull cord to start it and it`s roughly just over 250cc (10 cubic inches), manual choke.

I`m making a petrol generator with it.

[entwined]

it`s not a car' date=' it`s a 1977 Briggs & Stratton engine currently mounted to a board, single piston, horizontal shaft, and a large magneto flywheel is the only electrics on the thing, it`s a pull cord to start it and it`s roughly just over 250cc (10 cubic inches), manual choke.

I`m making a petrol generator with it.[/quote']

 

OK. What you have is a carberation problem. My guess is that it is not getting choked enough to start properly and/or to run properly when started.

 

If you either adjust or rebuild the carberator, it will start and run properly (again, my guess).

 

If, on the other hand, you are using it for experiments involving fuel mixtures, then perhaps it is already what you want?

[YT2095]

actualy I have stripped down and rebuilt the carb after a good cleaning, in fact every sinle part of the engine has been taken appart, cleaned and reassembled again (if was VERY VERY sick when I 1`st bought it). it`s working several orders of magnitude better that when I 1`st had it, and runs beautifully when warmed up, it`s just the starting of it? I can get a reasonable start with the choke 1/3 on any more or less and it`s no dice (or a dislocated shoulder from repeated pull starts).

another thing I`ve noriced that May be indicative or helpfull to you, is that at 1`st when it seems to be running ok, if I open the throttle to full, it`ll stall?

it seems to have to run on idle for a good few minutes of perfect tickover before you can throttle up,,,, not sure if that`s usefull in anyway to you as a diagnostic symptom?

 

there really is nothing anyone can say about checking X Y or Z for clean or blockages though, every aspect is Spotless now right down to the last ball bearing!

 

and no, it`s not an engine for testing fuels on, I`ve got far too much respect for it for that kind of thing, it`s basicly going to be a Bench engine primarily as an electrical generator and as a "Prime Mover" for other belt driven applications (maybe even a Go-Cart if my wife gets her own way), so it`s a Module more than anything.

[Phi for All]

Making the fuel more volatile helps for starting but once the engine is warm that mixture would likely cause vapor lock, especially in warm weather. If the fuel gets vaporized before it reaches the carb due to higher volatility you'll lose power or stall.

 

I like doG's suggestion. Figure on using ether to prime the cold engine and make it easier on yourself by rigging a dispenser for it. Maybe a foot pump to free both hands?

[YT2095]

yeah, I like that one too, and have been running through different mental/thought experiments as to how this could be implemented most effective and efficiently without breaching the filtering of the air intake directly.

I know the fuel that they sell you in the winter is NOT the same as that sold to you in Summertime (roughly about 8 changes a year at your local gas station!), I just wondered if a tiny altering of the fuel maybe the answer? I`ll try it anyway, and post the results just for data purposes.

[entwined]

What you discribe is an engine that it "running too lean" meaning that it is getting too much air for the amount of fuel it is getting.

 

If there is a fuel/air mix screw adjustment, try monkeying around with it when the engine is running. Usually by turning the screw one way ot the other, you will hear the engine "smooth out" and run a little faster.

 

Also, check and be sure that the gasket under the carb is not leaking allowing air to be drawn into the engine from under the carb.

[YT2095]

well the only thing that leads me to beleive otherwise (and I did consider that idea) is that the spark plug when removed after half hour or so is Black and not white, when it should be at ideal a redish brown.

although I no longer get clouds of smoke come from the exhaust anymore and jet black soot on occasion, when I take her from tick over to full throtle instantly, I`ll get a bit of grey/white smoke for a second, and on carb fuel air adjustment, the revs will race up and the exhaust pan will start to glow bright orange/yellow and I`ll get blue flames shoot out.

when I suddenly drop the revs the blue fire will REALLY Shoot out for a good 18 inch+ with a BANG! and then all`s back to normal again.

it`s an OHV single cylindar, and runs just great when warm, so whatever the problem is, it`s only something silly.

I just can`t figure what it might be?

[entwined]

I just can`t figure what it might be?

 

Neither can I.

 

Perhaps if I was 5000 miles closer, I would pop over for a look. Us hillbillys are good with engines.

[YT2095]

why that`s mighty friendly of ya there neighbour, I`m sure w`yall could whip up some crawdads and grits fer yer efforts

[entwined]

why that`s mighty friendly of ya there neighbour, I`m sure w`yall could whip up some crawdads and grits fer yer efforts

 

I ain't that kind if hillbilly. I eat the same food as the rest of America does - pizza and beer.

 

You boys have pizza and beer in England?

[doG]

why that`s mighty friendly of ya there neighbour, I`m sure w`yall could whip up some crawdads and grits fer yer efforts

I'll take some of them eff'n entwined won't. ah was born an' raised an Ozark hillbilly t'a flatlan'er fum Noo O'leans.

[YT2095]

You boys have pizza and beer in England?

 

well I do declare that to my reconing we HAVE heard of such new fangled things in this here neck of the woods

 

anyway as to not stray TOO far off topic, I`ve made 3 basic fuel mixes here, and I`ll try them out as soon as possible. it Might also be that the engine oil itself gets a bit thck in the cold too, when I replaced it, i didn`t exactly buy the BEST on the market, I just went for anything that was new and Cleaner that the existing black gloop that was over 20 year old!

I think it was a 20/40 I put in, but non the less, I should seek a better one when this has diluted all the crap in there!

[doG]

I`ve made 3 basic fuel mixes here, and I`ll try them out as soon as possible.

You might try adding a wee bit of acetone too. I've heard it helps the fuel atomize a little better coming out of the carb. The mixtures I've seen suggested 1 - 3 oz. in 10 gallons.

[YT2095]

Hmmm... I have plenty of that also, I may just give it a try

 

btw, this octane booster/lead replacement stuff is really quite expensive for what it is, wouldn`t adding Parafin (Kerosene) do the same thing?

I can buy 5 litres of parafin for £3.20.

[doG]

btw' date=' this octane booster/lead replacement stuff is really quite expensive for what it is, wouldn`t adding Parafin (Kerosene) do the same thing?

I can buy 5 litres of parafin for £3.20.[/quote']

Yep. I also added diesel to gasoline to up the octane. It adds a lubricating quality to the gas as well.

[YT2095]

Nice one!

 

btw, I tried the Acetone yesterday, no dice, it simply wasnt having it at all

although I WILL keep up with that acetone addition as it does no harm whatsoever and increases miles-per-gallon anywhere from 6.5 to 20% more according to data, so it`s worth adding it anyway, btw, optimum according to my reconing is about 2.3ml per Litre (less clumsy than 2 to 3oz per 10 gallons).

 

the ether spray into the airintake worked a charm though, so I`m seriously considering a thin copper pipe soldered into a drilled hole just above the carb inlet in the air filter and some sort of Jet delivery system.

it`s not ideal I know, but needs must when the devil rides!

[DV8 2XL]

the ether spray into the airintake worked a charm though, so I`m seriously considering a thin copper pipe soldered into a drilled hole just above the carb inlet in the air filter and some sort of Jet delivery system.

 

Don't. Not unless you want to throw a rod, bust a cam, or crack a piston. It's a crap shoot every time you use that stuff.

[YT2095]

well, non of the above really, but what option do I have?

It worked, a spray into the air filter a few yanks at the cord, and it started!

and started long enough to "warm up" and do the rest on it`s own afterwards.

it IS only a single piston engine, so I don`t envisage too much of a problem fitting a system like that I mentioned just to get it started, basicly a delivery system that will enter in X amount of ether when I push a primer, and that`s it

I wasn`t thinking of running it with it constanlty ON !

[doG]

It worked, a spray into the air filter a few yanks at the cord, and it started!

That's all the truck systems do that I've seen, they spray the air filter just to make the intake air volatile.